Thermostat Setting

ThisIsWeird

moneysaver1978 said:

That said, could a modern well-insulated house ever go down to 12oC?

Yes, it will - unless there's some source of heat. That could be from the warm bodies inside, or from solar gain.

But without any heat, equilibrium will be found with the outdoors.

Eldi_Dos

scottishsavingsgirl said:

We live in Glasgow and obviously this week the temperature has dropped significantly. This morning it's -7 outside.

On the east coast here but very similar temperatures, the saving grace has been the clear sky during the day and night which has kept the humiditity levels low.During the day the solar gain in south and west facing rooms has been noticeable if doors have been kept closed.

The only difference we have made to heating regime is leaving dehumidifier in the hall on twenty four hours,rather than turning it off in a evening.
The thermostat (in coldest room in the house) is set to 15 deg between 11 and 6 in the morning and to my knowledge has never kicked in during the night. The added advantage is a lot less condensation on bedroom windows in the morning and the first cup of tea tastes good due to having a bit of a drooth.

moneysaver1978

ThisIsWeird said:

moneysaver1978 said:

That said, could a modern well-insulated house ever go down to 12oC?

Yes, it will - unless there's some source of heat. That could be from the warm bodies inside, or from solar gain.

But without any heat, equilibrium will be found with the outdoors.

Yep but surely it would take longer and slower for the house to reach 12oC - in fact, that temperature may not be reached until the "on" mode kicks in bring the temperature up.

So in theory a family in a new well-insulated house may have 3 "on" and 3 "off" (properly off) and be comfortable but a family in an old house (with as much insulation as possible like loft insulation) may need to have 3 "on" and 3 "off-ish".

Although, I am not an expert and I am just theorising

grumbler

moneysaver1978 said:

ThisIsWeird said:

moneysaver1978 said:

That said, could a modern well-insulated house ever go down to 12oC?

Yes, it will - unless there's some source of heat. That could be from the warm bodies inside, or from solar gain.

But without any heat, equilibrium will be found with the outdoors.

Yep but surely it would take longer and slower for the house to reach 12oC - in fact, that temperature may not be reached until the "on" mode kicks in bring the temperature up.

So in theory a family in a new well-insulated house may have 3 "on" and 3 "off" (properly off) and be comfortable but a family in an old house (with as much insulation as possible like loft insulation) may need to have 3 "on" and 3 "off-ish".

Although, I am not an expert and I am just theorising

It was a general question - and the answer was general too.
However, the best modern habitable houses theoretically can have comfortable temperature inside even without heating at all. They are heated by human bodies and by the waste heat produced by appliances. Ventilation recovers heat from the air leaving the house.

ThisIsWeird

moneysaver1978 said:

ThisIsWeird said:

moneysaver1978 said:

That said, could a modern well-insulated house ever go down to 12oC?

Yes, it will - unless there's some source of heat. That could be from the warm bodies inside, or from solar gain.

But without any heat, equilibrium will be found with the outdoors.

Yep but surely it would take longer and slower for the house to reach 12oC - in fact, that temperature may not be reached until the "on" mode kicks in bring the temperature up.

So in theory a family in a new well-insulated house may have 3 "on" and 3 "off" (properly off) and be comfortable but a family in an old house (with as much insulation as possible like loft insulation) may need to have 3 "on" and 3 "off-ish".

Although, I am not an expert and I am just theorising

You are right, and I was just answering the physics Q :-)
In practice, even poorly-insulated homes are unlikely to reach outdoor temps even without any heating, because of solar gain, and the building fabric holding on to some warmth during the night.
And also, as the indoor temp falls towards the outdoor temp, the rate of loss decreases, prob exponentially, so takes longer to fall further. 

Albermarle

jennifernil said:

scottishsavingsgirl said:

We live in Glasgow and obviously this week the temperature has dropped significantly. This morning it's -7 outside.

Usually we turn our thermostat off at night, but when we get up in the morning the temperature is about 14. It takes a few hours to reach 18 when we turn it off. Then it's turned on again for a couple of hours in the afternoon, and then about 6pm until we go to bed.

Last night I left it on, set at 16, and the house is lovely and toasty this morning.

Is it better to have do this and have a "set" temperature all the time including at night, rather than turning the thermostat on and off? What uses more energy?

We have loft insulation, in a 1930s semi detached property, no other insulation (cavity etc).

We are just north of Glasgow, it was indeed  very cold last night.

 If you only have one thermostat controlling your heating, then I would say you need to invest in a few more controls.

It sounds like you have no timer, is that correct?   The most  basic system would be a timer you can set to turn on and off the heating, set it to come on about an hour before you get up, and off 30 minutes before you go to work.     On about an hour before you get home from work , off 30 minutes before bedtime, or whatever  variations  you need.  Then your thermostat can control the temperatures you need.    And generally you would be leaving it at the same comfortable for you setting.   

 As already said, the 2 functions can be combined into a "programmable thermostat".

You do however need to find the best position for the thermostat so the various rooms achieve the temperatures you want.

Much better IMO would be to use a timer plus thermostatic radiator valves so you can set different temperatures in each room.  These are usually combined with a main thermostat, generally in the lounge, where you do not fit a TRV.  I am not a fan of this method as the stat is in charge and will turn things off when the place it is in reaches the set temperature, but other rooms may not be warm enough.

For 35 years we operated our system using only a timer and TRVs on all but one small "bypass" radiator.......one that was always allowing water flow should all the TRVs close the other radiators.  The pump would run all the time and the boiler went on and off according to the boiler thermostat.    Not the most efficient of methods, but it worked well and allowed all rooms to have their own temperature setting.

However, better systems have been available for a while now, some of them have many features and can be quite complex to set up.

Having finally fitted a new, more efficient boiler in 2022, we looked at what was available and decided to go down the route of Smart Thermostatic Radiator  Valves, nothing too complicated, just new control heads that replace the existing TRV heads.    This means you do need to have ordinary TRVs on your radiators to start with.     

 There are several systems available, some more expensive than others.   With smart TRVs you fit one to each radiator, though your system may still require a bypass pipe or radiator.   We just retained the very small radiator in our very big hallway for this purpose.

So now we can set every room in the house to heat to its required temperature at the required time, settings are done via a phone app or on some other device.    Check out systems such as Wiser.....Hive.....tado.......google Smart Radiator Valves and Smart Heating Controls.........you should see plenty of options.     Screwfix has some good prices on some of them, but do shop around

Regarding the sentences in bold, that is also how I operate our CH system. In fact there is a room stat, but it is turned up to > 30 degree so always switched on. The reason is exactly what you say, a roomstat is dependent on the room it is in, and may turn the heating on or off at times inappropriate for other rooms.
I said this on another thread but the ( nice ) experts on here tended to disagree with this method.
One difference to you is that I will manually turn the heating off from time to time, depending on weather, family activity etc and at night.

jennifernil

Albermarle said:

jennifernil said:

scottishsavingsgirl said:

We live in Glasgow and obviously this week the temperature has dropped significantly. This morning it's -7 outside.

Usually we turn our thermostat off at night, but when we get up in the morning the temperature is about 14. It takes a few hours to reach 18 when we turn it off. Then it's turned on again for a couple of hours in the afternoon, and then about 6pm until we go to bed.

Last night I left it on, set at 16, and the house is lovely and toasty this morning.

Is it better to have do this and have a "set" temperature all the time including at night, rather than turning the thermostat on and off? What uses more energy?

We have loft insulation, in a 1930s semi detached property, no other insulation (cavity etc).

We are just north of Glasgow, it was indeed  very cold last night.

 If you only have one thermostat controlling your heating, then I would say you need to invest in a few more controls.

It sounds like you have no timer, is that correct?   The most  basic system would be a timer you can set to turn on and off the heating, set it to come on about an hour before you get up, and off 30 minutes before you go to work.     On about an hour before you get home from work , off 30 minutes before bedtime, or whatever  variations  you need.  Then your thermostat can control the temperatures you need.    And generally you would be leaving it at the same comfortable for you setting.   

 As already said, the 2 functions can be combined into a "programmable thermostat".

You do however need to find the best position for the thermostat so the various rooms achieve the temperatures you want.

Much better IMO would be to use a timer plus thermostatic radiator valves so you can set different temperatures in each room.  These are usually combined with a main thermostat, generally in the lounge, where you do not fit a TRV.  I am not a fan of this method as the stat is in charge and will turn things off when the place it is in reaches the set temperature, but other rooms may not be warm enough.

For 35 years we operated our system using only a timer and TRVs on all but one small "bypass" radiator.......one that was always allowing water flow should all the TRVs close the other radiators.  The pump would run all the time and the boiler went on and off according to the boiler thermostat.    Not the most efficient of methods, but it worked well and allowed all rooms to have their own temperature setting.

However, better systems have been available for a while now, some of them have many features and can be quite complex to set up.

Having finally fitted a new, more efficient boiler in 2022, we looked at what was available and decided to go down the route of Smart Thermostatic Radiator  Valves, nothing too complicated, just new control heads that replace the existing TRV heads.    This means you do need to have ordinary TRVs on your radiators to start with.     

 There are several systems available, some more expensive than others.   With smart TRVs you fit one to each radiator, though your system may still require a bypass pipe or radiator.   We just retained the very small radiator in our very big hallway for this purpose.

So now we can set every room in the house to heat to its required temperature at the required time, settings are done via a phone app or on some other device.    Check out systems such as Wiser.....Hive.....tado.......google Smart Radiator Valves and Smart Heating Controls.........you should see plenty of options.     Screwfix has some good prices on some of them, but do shop around

Regarding the sentences in bold, that is also how I operate our CH system. In fact there is a room stat, but it is turned up to > 30 degree so always switched on. The reason is exactly what you say, a roomstat is dependent on the room it is in, and may turn the heating on or off at times inappropriate for other rooms.
I said this on another thread but the ( nice ) experts on here tended to disagree with this method.
One difference to you is that I will manually turn the heating off from time to time, depending on weather, family activity etc and at night.

With the new Smart valves, I have set up a heating schedule with minimum overnight temperatures of 11-13 degrees, so it very, very rarely comes on, previously we had it totally off overnight, both methods give pretty much the same result, we never have heated the house overnight before.    It was -9 outside early this  morning, I did hear the boiler running for short intervals overnight to heat a room somewhere in the house, probably a room downstairs at the back as that gets no sun at all.

The front faces almost directly south, and our living rooms are upstairs, so we do gain a lot of heat  there when the sun shines, those rooms never drop below 15-16 degrees overnight.

We are retired, but look after our grandchildren 2 days per week, so the schedule is for everything to be at no more than 14 degrees between 10.30 and 16.30, and on the days we are home we can easily turn various rooms on as necessary.  It is also useful to be able to remotely delay the heating coming on if we will be getting home later than expected, or to turn it on earlier if plans change.

When we got the new boiler we told our fitter that we were planning to get a Smart system so did not need him to fit a thermostat meantime, if he had insisted then we would have done as you do and just turned it up to max.   

So far, very pleased with our new boiler and controls, between them we have reduced our gas use from 28000 kWh to 16000 kWh.......house is large  (280 sq m) with some high ceilings, and we like to be warm!

Albermarle

So far, very pleased with our new boiler and controls, between them we have reduced our gas use from 28000 kWh to 16000 kWh.......house is large  (280 sq m) with some high ceilings, and we like to be warm!

A new condensing boiler compared to a 35 year old one, should save at least 20% in gas, maybe more, as long as the boiler flow temperature is not too high.

We use about 16000KWH in a year, also in an older house with high ceilings etc but not as large as 280 M2.

However there is at least one person in the house nearly all the time, including someone with extra demands for warm rooms.

jennifernil

About half of our upstairs rooms have high ceilings, but the house is not that old, only 36 years, timber frame so pretty well insulated, though not as well as today's newbuilds.