Cavity wall insulation and thermostat

r2015

Well that doesn't work,


Get cavity wall insulation and you will be able to save on energy by lowering your thermostat setting a few degrees.


I got cavity wall insulation and have had the heating on for a few days, it's cold here in Scotland, outside temp 13 deg C at present.


I usually have the thermostat set so the room heats to 22 deg C according to the thermometer sitting on top of the thermostat which on my thermostat is 6.5.


So I turn the thermostat down to 6 and the temperature drops to 20 deg C.


Turn it back to what it has been set at for the past 24 years and the temperature goes back to 22 deg C.


So cavity wall insulation does not magically raise the temperature higher than the thermostat setting.

Where's the sarcastic smiley when you need it?

Smiley_Dan

No, but the idea is that less energy is required to get you to your chosen temperature.

22 deg is pretty hot btw. Normally the warmest rooms (lounge, bathrooms) would aim for max 21.

r2015

22 deg is pretty hot btw

No its not.


My point is that the cavity wall insulation installers propagate a myth that you can turn your thermostat down and still get the same temperature.

matelodave

Not only does it take less energy to get to your chosen temperature it also takes less to maintain it so you should find that the room cools down more slowly. This means you could possibly drop your thermostat setting by a degree or two and not notice the difference as you won't get the temperature swings.
Perhaps if you set your thermostat to 6 before you had the insulation the room temperature would have dropped to 18 or even lower

CashStrapped

Firstly; a thermostat does not change the temperature of the heating. All it does is signal the boiler to turn off when that temperature is reached.

So whatever you set it to, the boiler will chug away untill that temperature is reached, then turn off. When the temperature drops, the boiler will kick in to raise the temperature again.

With cavity wall insulation, the room should stay warmer for longer, maintaining the temperature you set on your thermostat. This would mean the boiler has to kick in and turn on less, hence less waste in gas.

So, back to the original quote, as the room stays warmer for longer, you maybe comfortable turning down the thermostat 1-2 degrees as the room will maintain that temperature for longer, saving you more money.

System

r2015 wrote: »

No its not.


My point is that the cavity wall insulation installers propagate a myth that you can turn your thermostat down and still get the same temperature.

I confess that I have never heard of any such 'myth'. The truth is as MD states. You should find that it takes less time to heat a room to a given temp and less time for the temp to fall. Together, this results in reduced energy consumption and less cost to the energy consumer. It is also true that if you turn your thermostat down, you will lose less energy.

Think of cavity wall insulation as being akin to a vacuum flask. The reason that tea stays hot in a flask is because the heat cannot transfer across the vacuum. Cavity wall insulation is a physical barrier which as prevents heat transferring from inside to out. Similarly, it should keep your house cooler in the summer.

Smiley_Dan

The advice to turn your thermostat down *does* exist as the OP states. However, I think that's related not to CWI as such, but general behaviour changes, i.e. putting up with a bit cooler.

CWI may allow a reduction in a thermostat if it means air tightness of the building fabric is improved. This can be the case for EPS and foam insulants, although not for fibre nor batts (obviously the last one isn't installed in this case). In other cases, a retaining of heat in the thermal store in the wall (assuming masonry) will radiate heat back into the room, further improving its comfort and allowing a lower air temperature.

22 is, well, not "hot" maybe, but warmer than it needs to be. Depending on surface temperatures, humidity and air movement you can actually have the air temperature much lower.

Smiley_Dan

The other thing is the fabric of your building is but one factor. You can have 300mm XPS insulation around your house, but if your air changes are high then all that heat will just be leaving the house.

captainhindsight_2

It sounds like you have misunderstood what cavity wall insulation does, it des not contribute towards your heating at all. What it does is trap in the heat you generate, if you imagine a tea cosy on a pot of tea it does not make the tea pot hotter it just keeps it hot for longer.

You should leave the thermostat at a temperature that you feel comfortable somewhere between 18-21 is common, because of the insulation trapping in the heat the boiler will raise your home to that temperature quicker and it will take a much longer time for it to come on again because less heat is being lost through the walls.

When you get you gas bill or if you check your meter you will notic you will be using considerably less gas to maintain the same temperature you had before.

r2015

It sounds like you have misunderstood what cavity wall insulation does,

I haven't, it is the cavity wall installers that don't know how it works.

I have a leaflet that says Get cavity wall insulation and you will be able to save on energy by lowering your thermostat setting a few degrees.

As I sarcastically said Where's the sarcastic smiley when you need it?

if I lower my thermostat the temperature becomes lower.

If the temperature gets lower I feel cold so I raise the temperature.
Isn't that how thermostats work?

kaya

If you set a thermostat to 20deg and the temperature inside becomes much over the set temperature that means
1) your thermostat is broken
2) it's very sunny outside

I have no idea why anybody would think that would or could be changed by cavity wall insulation?