SensoCOMFORT Room Temp Mod: Inactive, Active or Expanded?

SensoCOMFORT Room Temp Mod: Inactive, Active or Expanded?

The Room Temp Mod setting on the Vaillant SensoCOMFORT controller can dramatically change how your heat pump behaves. In this guide we take a deep dive into what Inactive, Active, and Expanded really mean – how each interacts with weather compensation, OT thresholds, and Energy Integral – and which option may be best for your system.

This article (updated September 2025) is part of my wider series of Vaillant Arotherm guides, aiming to demystify the settings that matter most for efficiency and comfort.

Vaillant Arotherm Heat Pump Guide: Weather Curve, Hot Water Modes, SensoCOMFORT, COP & SCOP

Table of Contents

This article about the Sensocomfort: Room Temp Mod is a comprehensive read.

Use the Table of Contents below to jump straight to the section that matters most — or scroll through at your own pace.

Key Concepts You Should Know

Here are four essential settings / internal mechanisms that Room Temp Mod works with — understanding these will make the rest of this guide more meaningful:

OT switch-off Threshold

The Outside Temperature (OT) switch-off threshold acts as a gatekeeper for your heating system. As long as you have a heating schedule running (or you’re in manual mode), the OT threshold decides whether the heat pump is even allowed to run.

You’ll find it here on the SensoCOMFORT controller:

• Settings
• Installer Level
• 00
• Installation Configuration
• Circuit 1
• OT switch-off threshold

The default is 16 °C, which means:

• If the outside temperature is below 16 °C, the heating is allowed to run.

• If the outside temperature is 16 °C or above, the heating is disabled.

Quick Example

Let’s say it’s a mild spring day:

• At 15 °C outside, the OT threshold allows heating. If your schedule says “on,” the system can fire.

• At 17 °C outside, the OT threshold prevents heating entirely, no matter what your schedule or room target says.

This can be a blessing (avoids unnecessary heating on warm days), but it can also clash with reality:

• Sunny 16 °C outside → your south-facing rooms may be toasty, but the north side of your house could still be chilly.

• Overnight drops → if the house holds its heat well, the heat pump might still click on simply because outside has dipped below threshold, even though indoors is fine.

Why It Matters

The OT threshold is simple but blunt. It doesn’t consider indoor comfort, only outdoor temperature.  But it’s starting point as to whether your heating comes on or not.

Arotherm Control Methods

Once heating is enabled (OT Threshold), there are two main ways the Arotherm controls heat going into your home:

1. Weather Compensation Curve (primary)

2. Room Temp Mod (secondary)

Plus a third layer worth knowing: Energy Integral.

Let’s look at each of these in more detail.

Weather Compensation Curves

The primary way to control how much heat your Arotherm delivers into your home, whether that’s through radiators or underfloor heating (UFH),  is by setting the weather compensation curve correctly.

The principle is simple:

• Your house is constantly losing heat to the outside world.

• The heat pump’s job is to replace that heat at the same rate.

• The curve tells the system how hot the water in your rads/UFH should be at a given outdoor temperature to keep things in balance.

It does this by combining three things:

1. Your chosen indoor target temperature

2. The curve setting you’ve picked

3. The current outdoor temperature

From those three inputs, the controller doesn’t calculate from scratch, it simply looks up the required flow temperature from preset tables stored in the curve data.

👉 In other words: at that indoor setpoint, that curve value, and that outside temperature, the same flow temp will always be chosen.

Example from Vaillant’s Curve Diagram

Displayed above is a table from my own curve analysis, which we’ll use to show how the heat pump chooses the flow temperature based on the three elements noted above (indoor temp, curve setting, and outside temp).

• Indoor target temperature: 20.0 °C (yellow box, red circle)

• Curve setting: 0.6 (green box, blue circle)

• At 10 °C outside (blue box) → target flow temperature is 31 °C (where the green and blue meet, orange circle).

• If the outside temp drops to 0 °C → flow temp rises to 38 °C (purple circle).

• If the outside temp rises to 5 °C → flow temp falls to 35 °C (pink circle).

• At 15 °C outside → flow temp is 26 °C.

• At -3 °C outside → flow temp rises further to 40 °C.

This is weather compensation in a nutshell:

• Hotter system water when it’s colder outside.

• Cooler system water when it’s warmer outside.

Mini Table: Curve 0.6, Indoor Target 20 °C

Tuning the Curve

• If your house isn’t reaching target indoor temp, you may need to raise the curve (hotter water into rads/UFH).

• If your house is getting too hot, you may want to lower the curve.

But remember:

• Higher flow temperatures = lower efficiency (lower COP).

• The art is finding the lowest curve that still keeps you comfortable.

Menu path (on the SensoCOMFORT controller):

Vaillant aroTHERM Weather Curve & Heating Curve Guide

Energy Integral

The Energy Integral is Vaillant’s internal counter that decides when to start and stop heating cycles.

It works like this:

• The controller constantly compares the actual flow temperature (water in your rads/UFH) against the target flow temperature (from the weather curve and Room Temp Mod).

• The bigger the gap, the faster the counter adjusts up or down.

• Because that difference can be either positive or negative, the counter can move in both directions.

Default behaviour:

• Heating cycles start at –60 (this is the default, but it can be adjusted by an installer down to –100).

• Heating cycles stop at 0.

We’re getting into fairly deep territory here — which is why this part is mainly for the nerds.

Why It Matters

• For most homeowners, you don’t need to worry about Energy Integral, it works quietly in the background.

• For installers and advanced tinkerers, it’s another tool in the arsenal: understanding how it works can help explain cycling patterns and improve system setup.

• On firmware version 351.06.07, there was a bug where Energy Integral effectively double counted, leading to more frequent cycling. This issue was fixed in version 351.09.01 and later, so current installs shouldn’t be affected.

Energy Integral also interacts with Room Temp Mod:

• In Inactive and Active modes, Energy Integral is the boss (aside from OT threshold).

• In Expanded, Energy Integral can be overridden by the thermostat on/off rules.

If you want the full technical breakdown (with graphs, examples, installer tips, and details on the firmware bug), see my dedicated article: Vaillant Arotherm Energy Integral Deep Dive.

Vaillant Arotherm Firmware 351.06.07 Problems (Energy Integral)

Room Temp Mod Summary

Once you’ve got your weather compensation curve set up properly, the next layer of control is the Room Temp Mod setting on the SensoCOMFORT.

This setting decides what role your room controller plays in adjusting the system. In plain English: does the controller just display info, gently tweak things, or actively switch the heating on/off?

Here are the three options:

• Inactive → Pure Weather Compensation. Flow temperature is based only on outside temperature and the curve. The room controller is basically just a display.

• Active → Weather Compensation + Room Influence. Flow temperature can be automatically nudged up or down depending how far the actual room temp is from the target.

• Expanded → WC + Room Influence + On/Off Control. Acts like a traditional thermostat, turning the heating off if room temp exceeds target, and back on when it drops.

⚠️ Note: To use Active or Expanded properly, the SensoCOMFORT needs to be in a habitable room (living room, hallway, etc.), not in a plant room, airing cupboard or garage.  This is because is needs to read and accurate and representative room temperature to make decisions upon.

Menu path on the SensoCOMFORT controller to change Room Temp Mod:

• Settings
• Installer Level
• 00
• Installation Configuration
• Circuit 1
• Room temp. mod.

From my own experience over several winters with the Arotherm, I’ve found Active is the best choice for most homeowners. It gives you the stability of weather compensation, but with just enough room influence to react to everyday life (doors opening, solar gain, cooking, etc.). We’ll look at the detail of why in the next sections.

Room Temp Mod: Active

Active = Weather Compensation with added Room Influence.

That means the system still follows the weather curve as its primary guide, but now it also pays attention to the actual room temperature measured by your SensoCOMFORT. If the room is below target, it can automatically nudge the flow temperature up; if the room drifts above target, it can nudge it down.

Example in Action

Here’s a classic example of Active mode at work.

On a cold morning (around 4 °C outside), I opened the back door for 20 minutes (9:20am). The indoor temperature (black line) started to drop, and the SensoCOMFORT reacted by increasing the target flow temperature (grey line).

• Flow temperature (red line) spiked upward.

• Heat output (yellow line) increased.

If the situation were reversed, say a bit of solar gain through the windows and the room temperature rose quickly, the controller would have done the opposite, lowering the flow temperature to avoid overheating.

That’s Active in a nutshell: it reacts to real-world indoor conditions by automatically nudging the flow temperature up or down.

My Experience

I’ve run my Arotherm in Active mode for several winters now, and it’s the mode I recommend for most households. It doesn’t need the weather curve to be dialled in perfectly, just close enough. Active will handle the little swings caused by cooking, people, sunshine, or doors being left open.

But don’t expect miracles, the adjustments are small. If your house is way off target (say, several degrees), Active won’t close that gap quickly. In my experience, it only shifts the flow temperature by a degree or two. I often wish there was a setting to make it more aggressive.

Energy Integral Interaction

When using Active, the Energy Integral is still in charge of starting and stopping heating cycles (aside from the OT threshold). Active just tweaks the flow temperature within those runs.

Room Temp Mod: Inactive

Inactive = Pure Weather Compensation.

In this mode, the SensoCOMFORT ignores the room temperature entirely. The flow temperature is chosen only from the weather curve (outdoor temp + target indoor temp + curve setting). The room controller is basically just a display.

Example

Using the same back-door test as before:

• In Active, the system responded by automatically nudging the flow temperature up to compensate.

• In Inactive, nothing would have changed. The heat pump would have just kept running at the same flow temperature, unaware the indoor temp was falling.

This means it would likely take longer for the house to recover to target after disturbances (like doors opening or a cold draft).

Why Use Inactive?

I can see the appeal of the “purist” approach, relying solely on weather compensation, with no indoor interference. If your curve is perfectly tuned, it works.

But for most homes, I can’t see a good reason not to use Active. It gives you all the benefits of weather compensation plus the safety net of room influence. If you stick with Inactive, you’ll never have that option.

Is there an advantage to Inactive over Active that I’ve missed?

⚠️ The only time you’re really forced into using Inactive is if your SensoCOMFORT controller isn’t in a habitable room (e.g. it’s in a plant room, airing cupboard, or garage), so you’re reading unhelpful indoor temperatures. Otherwise, Active is almost always the smarter choice.

Energy Integral Interaction

Just like in Active mode, Energy Integral is still the primary control for cycle start/stop (aside from the OT threshold) when in Inactive mode.

Room Temp Mod: Expanded

Expanded = Uses both Weather Compensation and Room Influence, but on top of that also acts as an on/off thermostat, switching the heating off if room temp is exceeded.

One thing to remind everyone of: the SensoCOMFORT controller can be used on both heat pumps and gas boilers. I think Expanded mode exists mainly to mimic a boiler-style thermostat for gas systems.

The SensoCOMFORT manual explains it like this:

• Heating deactivates if the room temperature is 0.125 °C above target.

• Heating reactivates when the room temperature falls 0.1875 °C below target.

That’s a very narrow bandwidth of control.

For example, if we had a target room tempeature of 20C.

• Heating switches off: 20.13C
• Room target: 20C
• Heating switches back on: 19.81C

Note: numbers rounded up a little

With a heat pump, you generally want long, steady runs at low flow temperatures (“low and slow”) or let Energy Integral deal with heating cycles.

Expanded risks chopping that up into more on/off cycling than Inactive or Active.

So I can’t personally recommend Expanded unless there are exceptional circumstances. My preference is to get the weather curve dialled in and then use Active to smooth out the rest.

Real-World Behaviour

I tried Expanded for a week, and here’s what I observed.

In this short example, the room temperature rises to 20.2 °C at 17:12 (target 20 °C), just above the 0.125 °C Expanded cut-off.

In Inactive or Active, the heat pump would have kept trickling a low amount of heat into the room. With Active, it would even have tried to reduce the flow temperature slightly to counter the rise.

But in Expanded, the heat pump shut off completely until the room cooled back down to 19.8 °C (0.1875 °C below target), which took over an hour.

That means a full compressor stop and then re-start cycle. And because start-ups use a lot of electricity, it’s not great for performance.  As you can see from the large amount of heat put into the room just after 18:00 (yellow on the graph).

For the nerds: at the time Expanded cut the cycle (17:12), the Energy Integral was still at –38, so in Active/Inactive it would normally have carried on heating.

Setback Behaviour

Another thing I didn’t like about Expanded was how it handled setback mode.

At 21:30, my system normally drops the target room temp from 20 °C to 19 °C via the setback feature.

In the Active mode example below you can see the grey line drop at 21:30 (indicating that setback mode drop the required flow temperature).

Note: setback still just picks the flow temperature from the curve, just at the lower target indoor temperature, ie 19C in this example.

The heat pump then cycles at 21:45 (due to Energy Integral), before needing to come again around 22:15, but still at the lower flow temp and it continued this through the night, maintaing 19C indoors.

This method ensures that the heat pump keeps running gently at that lower flow temperature. This trickles just enough heat in to limit heat loss overnight.

We can see totally different setback behaviour in this Expanded mode example below.

Same deal with setback though, it drops the required internal temperature drop from 20C to 19C at 21:30.  But because the hard stop temperature of 20.2C is reached at 21:09 the heat pump just goes off.  Even before setback started at 21:30.

The heat pump simply did nothing for three hours (21:09–00:00) as room temperature remained below setback target of 19C.  It was 19.1C in the room just before the hot water cycle started.

Only after hot water finished (02:30), does the heat pump start heating again, because the room temperature (18:4C) is below the setback target temperature of 19C.

So we had no heating from 21:09 through to 02:30 (almost 4.5 hours) and the room temperature dropped from 20.2C to 18.4C across that period.

When heating finally resumed, the heat pump had to work harder from a lower starting point, less efficient and less comfortable.

That’s why I prefer how Active handles setback. Smaller tweaks, more stability, fewer rollercoaster swings.

Sensitivity & Location

Another issue with Expanded is how much it relies on the SensoCOMFORT’s room sensor.

In my case, I have three other temperature sensors in the same room.  Because, of course!!!

All four tracked the same temperatures accurately, but the SensoCOMFORT was slowest to react to changes. With the wireless RF version, it only reports every five minutes. That means you could easily get 5–10 minutes of lag when triggering stop/start in Expanded mode.

That just adds more delay and inconsistency to the way it controls the system.

Note: this delay would obviously also present itself in Active as it relies on internal temperature too.  But because we aren’t doing hard on/off in Active it’s less of an issue.

Energy Integral in Expanded

• When room temperature is below target, Energy Integral behaves normally, starts at –60 (or whatever its been set to), and stops at 0.

• But once room temperature exceeds target by 0.125 °C, Expanded overrides and shuts the cycle down, regardless of Energy Integral.

• The Energy Integral counter is effectively paused until heating restarts.

When the system does restart, the flow water is usually cold, and the gap to target is large. Energy Integral can then plunge as low as –180 before recovering, meaning a long “catch-up” run.

This behaviour is also seen at the start/end of hot water runs (Integral pauses, then resumes).

When Expanded Helps

To be fair, there are niche cases where Expanded can make sense:

• Homes with big solar gain (south-facing rooms, large glazing) where you need a hard “off” when the sun does its job.

• Shoulder months (Sept/Apr) — warm in the day, cool at night. Expanded can prevent the heat pump from firing unnecessarily if the house is still above target indoors, even though outside is below the OT threshold.

But for most households, I wouldn’t recommend it. Expanded feels like boiler logic retrofitted to a heat pump. It’s less efficient, less comfortable, and doesn’t play to a heat pump’s strengths.

⚠️ In short: Expanded can work in very specific conditions, but I think Active is almost always the better choice.

One other observation from running four temperature sensors in the same place is that I always see the SensoCOMFORT consistently around 0.3C higher than all the other three.  So something to watch for in your own setup.

Inactive versus Active

To really see the difference between the two, I ran some tests switching between Inactive and Active mid-cycle.

In this example I was initially running Inactive mode, which is pure weather compensation, but I switched to Active to show the difference in behaviour.

The first cycle is using Inactive, then I switched to Active part way through the second cycle

At 15:59, the room temperature (black line) was 19.5 °C, while the target was 20 °C. The heat pump just carried on at the same target flow temperature (grey line), because Inactive only looks at the outdoor temp.

At 16:20, I switched to Active.

Straight away, the target flow temperature (grey line) increased. Why? Because the actual room temp (19.6 °C) was below the target (20 °C). That bump in flow temp nudged the room back towards target more quickly.

Then, as the room temperature climbed closer to 20 °C (around 16:40–17:00), you can see the target flow temp automatically lower again. That proves Active works both ways: increasing and decreasing flow temp depending on what the room needs.

Notice too that the outdoor temperature (purple line) was flat at around 9 °C, so the change had nothing to do with weather compensation. This was purely the room influence at work.

More Inactive versus Active

I also ran a second test, switching back and forth between modes while playing with different curve settings.

Here’s what I found with an internal room temperature of 21.5 °C and a target of 20 °C:

So you can clearly see that Active reduces flow temperature when the room is above target — roughly 2.5–3.0 °C for every 1 °C of room offset.

It’s almost like the difference chosen matches the 2.5 °C flow adjustment per 1 °C of room temperature from the weather compensation curve tables.

Whilst this helpful, in my experience Active still not aggressive enough. I’d like to see it respond more strongly to bigger indoor swings.

Quick Reference: Room Temp Mod Modes Compared

Here’s a summary of how the three modes stack up:

Pump Overrun Observations

One small but interesting difference between the modes is how the circulation pump behaves between heating cycles.

• Inactive → The pump continues to overrun non-stop between Energy Integral-driven cycles (albeit at a reduced flow rate).

• Active → Same behaviour as Inactive. Pump ticks along gently between cycles.

• Expanded → A bit different. The pump still overruns between cycles caused by Energy Integral, but if the heating has stopped because the room target has been met (Expanded’s on/off logic), then the pump shuts off too. It won’t fire up again until the next cycle starts (i.e. when the room temperature drops 0.1875 °C below target).

This might sound minor, but it’s worth noting: Expanded doesn’t just cut the compressor, it also cuts the circulation pump.

Summary, Flaws and Recommendations

Before diving into Room Temp Mod, it’s worth repeating: the weather compensation curve is the primary control of your heat pump. Get that dialled in first, then use Room Temp Mod as a secondary tool.

Here’s how I see the three modes after a few winters of living with them:

• Inactive → Fine if you’ve nailed your weather curve, or if your SensoCOMFORT is stuck in a plant room/garage where room influence makes no sense. But you’re giving up an extra layer of control.

• Active → My recommendation for most households. It’s smooth, efficient, and compensates nicely for everyday swings — cooking, doors open, solar gain, kids charging about, whatever. Not perfect, but the best balance.

• Expanded → Works, but I wouldn’t use it unless you’ve got a very specific edge case (big solar gain, or shoulder months where you want to stop heating when indoors is already toasty). Otherwise, it just feels too boiler-like.

Flaws I’ve Found

It’s not all rosy with Active. Over several winters I’ve found:

• Room influence isn’t aggressive enough. It’ll tweak flow temps a couple of degrees, but won’t save you from big mismatches.

• Seasonal curve tweaking is still needed. I often end up nudging my heat curve higher when it’s colder outside and dropping it again when it’s milder. It’s not a massive hassle (I bounce between ~0.45 and 0.5), but it does mean it’s not truly “set and forget.”

A small feature request to Vaillant: it would be great to have a more dynamic room influence — something that could automatically adjust more strongly when needed. Call it a “homeowner auto mode.”

⚡ Bottom line:

• Get your weather comp curve close.

• Put your SensoCOMFORT in a habitable room.

• Use Active as the sensible default.

• Save Expanded for rare niche cases.

Big shout out to the guys at Open Energy Monitor for their heat pump monitoring system.  This article would never have been possible without their kit.

You can monitor my system here: https://emoncms.org/energystatsuk

My system is also part of the growing list of systems taking part in the https://heatpumpmonitor.org/ project.

Smarter Control with Havenwise

Why I Looked Beyond Vaillant’s Controls

After three winters tweaking curves and settings on the Vaillant controls, I’ve got a good sense of where the shortfalls are. For the most part, Vaillant’s setup is excellent, better than most heat pumps.

But the limitations nag:

• Active mode isn’t aggressive enough in its room influence.

• Manual curve tweaking is still needed through the year.

That’s what led me to trial an alternative and perhaps a long-term solution.

What is Havenwise?

Havenwise is an online optimiser for a variety of heat pumps, including Vaillant.

Think of it as an extra brain for your system: instead of relying only on fixed settings like the OT threshold, weather compensation curve, or Room Temp Mod, it takes control and makes smarter, real-time decisions.

Rather than me constantly tinkering with curves and modes, Havenwise looks at the bigger picture: outdoor weather, indoor temperature, forecasts, tariffs, even how my house heats and cools. Then works out the most efficient way to run the heat pump.

And the best bit? If you already use the myVaillant app, you’re basically ready to go:

• No external box to buy

• Just your internet connection and the standard Vaillant internet controller

In short: Havenwise delivers the “Auto mode” Vaillant never built in — combining comfort, efficiency, and cheaper running costs without the fuss.

What Havenwise Does

• Connects remotely to your heat pump via the internet.

• Overrides the built-in Vaillant controls: OT threshold, weather compensation curve, and Room Temp Mod.

• Uses a much broader dataset to make decisions:

  • Current indoor temperature

  • Outdoor temperature

  • Weather forecasts

  • Time-of-use electricity tariffs

  • Learned heating/cooling behaviour of your home

Instead of rigid thresholds, Havenwise adapts dynamically, firing the heat pump only when the house actually needs it.

My Experience with Havenwise

Since trialling Havenwise, the difference has been clear: it simply makes better decisions.

For example:

• With a curve of 0.5, at ~9–10 °C outside, my Vaillant would normally target ~29 °C flow temp.

Havenwise instead chose 25 °C, because it “knew” the house was already near target.

You can see this shown in the graph below.

Instead of picking the nearest value from a preset list, Havenwise selects the right flow temperature for the situation.

The result:

• Better comfort

• Fewer unnecessary cycles

• Improved efficiency

Beyond the Basics: Tariffs & Hot Water

Havenwise isn’t just about smarter flow temps. It also:

• Integrates with time-of-use smart tariffs (Octopus Agile, Intelligent Go, Cosy, etc.) to schedule heating when electricity is cheapest.

• Builds a digital twin of your house, then uses predictive algorithms (weather forecasts + tariff data + house behaviour) to plan heating.

• Can also optimise hot water scheduling, heating your cylinder at the cheapest times while still meeting demand.

Who It’s For

Havenwise makes the most sense if you:

• Want heat pump optimisation without manual tweaking

• Value both comfort and lower running costs

• Are on (or considering) a time-of-use electricity tariff

• Want an “Auto mode” for heating and hot water

For many households, it’s a genuine fire-and-forget solution.

⚡ Havenwise isn’t free, but if you’re on a smart tariff or just want your system to quietly optimise itself, it’s definitely worth a look.

If you fancy giving it a go, you can start a free trial here and see how it works in your own house.

Frequently Asked Questions

What happens if I set Room Temp Mod to Expanded?

Expanded acts like a traditional on/off thermostat. Heating cuts off when room temperature goes just 0.125 °C above target, and only restarts when it drops 0.1875 °C below target. That narrow bandwidth means more cycling, which can reduce efficiency and comfort.

Why is my pump still running when the heating is “off”?

Even if heating is off between cycles, the circulation pump often overruns at a reduced speed. In Active and Inactive, it runs constantly between Energy Integral cycles. In Expanded, the pump will stop if heating is disabled due to room temp being met, but fires up again once heating is called for.

Does weather compensation ignore indoor temperature?

Yes. In Inactive mode, the controller only looks at outside temperature, curve setting, and target indoor temp. It won’t react to indoor swings (like solar gain or a door being left open) unless you use Active or Expanded.

If Active mode isn’t aggressive enough, what can I do?

You’ve got options:

• Adjust your weather compensation curve slightly.

• Make sure setback is used properly.

• Check your SensoCOMFORT is in a good location (habitable room, not a garage or plant room).

• If all else fails, Expanded mode or a smart optimiser like Havenwise can take things further.

Will Expanded mode save energy?

Not usually. It might help in very specific cases, like big solar gain in south-facing rooms, or during shoulder months when daytime is warm but nights are chilly. But most of the time, Expanded causes more cycling and comfort swings compared to Active.

Is there a firmware bug affecting Energy Integral / cycling?

Yes. Firmware 351.06.07 had a bug where the Energy Integral double counted, leading to unnecessary cycling. Vaillant fixed this in 351.09.01 and later. If you’re seeing odd cycling, check your firmware version.

Where should I put the SensoCOMFORT controller?

If you want Active or Expanded to work properly, it has to be in a lived-in room, like a lounge or hallway. Stick it in a plant room, garage, or cupboard, and you’ll get misleading results.

What is pump overrun?

It’s when the circulation pump keeps running between heating cycles. In Active and Inactive, it runs non-stop (albeit at reduced flow). In Expanded, it stops completely when heating is disabled due to room temp being met.

What about setback overnight?

Active handles setback gracefully, lowering the flow temperature but still trickling heat in. Expanded, on the other hand, may do nothing if the room is still above the setback target, which can cause big overnight temperature drops and more effort to warm back up in the morning.

Can I override the outside temperature (OT) switch-off threshold?

Not with the built-in Vaillant controls. The OT threshold is a blunt tool.  Heating is either allowed or not, based purely on outside temperature. If you want more flexibility, smarter systems like Havenwise can override it and make better decisions.

Does Room Temp Mod affect hot water?

No, Room Temp Mod only affects space heating. Hot water runs are controlled separately by your schedule and hot water settings. However, Energy Integral behaviour can be influenced during or just after a hot water run.

What is the best Room Temp Mod setting for efficiency?

For most homes, Active gives the best balance of comfort and efficiency. It adds room influence to weather compensation without the heavy cycling of Expanded. Inactive can work if your weather curve is dialled in perfectly, but that’s rare.

Should I change Room Temp Mod with the seasons?

Not directly. You’ll usually leave Room Temp Mod on one setting (Active, in most cases). What you may need to tweak with the seasons is the weather compensation curve, as colder or milder months might need slight adjustments. Smart systems like Havenwise can automate this.