Why is my home so cold??

[Freshstarts24]

I’m hoping someone might have some ideas as to what the issue could be. I live in a flat, have gas central heating. The flat is fairly old , but has double glazing and doesn’t feel particularly drafty.
No matter how long I have my heating on or what temp I turn the thermostat to it does not seem able to go above 21 degrees. Now, I’ve seen others mention on here that 21 is a reasonable temperature, but in my flat it still feels chilly. Whereas 21 in my office for example, would not be.
Surely it can’t be right that I can’t get the temperature any higher than this? It’s never warm. If I have the heating on for 5 hours, it stays at 21, and whilst no longer cold, it’s also not warm.

I rang whoever gives energy saving advice and they emailed me the EPC. Can't remember who it was and this was Scotland so I think different for rest of UK. I'm sure you'd find out easily uf you Google it.

Put silver foil behind all the rads on outside rooms so heat bounces back into room. Also as has already been advised get a separate thermometer - mine measures humidity too and check the actual temperature.

yes this, you need to draught proof your house.

Where is your thermostat? You need it to be in the coldest part of the flat rather than the warmest or other areas might not be at that temperature when the heating clicks off. That said, 21degrees should feel warm.

if you are renting your landlord had an obligation to provide the EPC on moving in (Energy Performance Certificate), similarly if buying they can’t be advertised without one and you can’t sell a property without a current one. You can look up the EPC for your property here https://www.gov.uk/find-energy-certificate

How old's the thermostat? Our 1970s one which we recently replaced was not telling the truth to us! Get a cheap thermometer and see what the temperature actually is at various points around the flat.

The first thing to do is test the temperature with a separate thermometer, I bought a pack of two cheap ones from Amazon and I use them to check the therm is recording correctly (it is - my problem was different, the temp is 15 but I still feel warm so I couldn't believe it was right).

Check the temp settings on the boiler, you may need to Google how to change it. If that is set low the therm can't demand more heat from it.

If both those are OK you may have to consider a new thermostat. You can get a decent one for £80, a fairly normal one for £35 or a fancy schmancy Nest for c£300. You may need someone to fit it for you. But when my boiler kept running continuously it was the therm that was the problem, it had malfunctioned and was constantly demanding heat, even though it was summer.

Possible reasons in order of ease of checking/rectifying:

Your thermostat could be in a warm place, so it turns off before the rest of the room/s is up to temperature.

The reading on your thermostat could be wrong, so it's less than 21 when it turns the heating off.

You could be losing heat through the windows. We have old double glazing and they leak heat quite badly. We have thermal lined curtains, which make a big difference when closed.

The insulation in the walls or ceiling could be poor and losing heat.

Another one here who has a dodgy thermostat, it’s old, so it’s a couple of degrees out - if I set it to 20 the room temp is 18 - so now we have it set at 23 and that gives us a room temp of 20/21

You say your curtains are “decent enough” but clearly not since they can make a big difference. Proper interlined curtains (the ones that are like mini duvets) make an enormous difference. It also helps to have both blinds and curtains. Do you draw your curtains the minute the sun goes down?

If there is an EPC this will be on the EPC register online. It's on the government website and you just need to put in your postcode to retrieve it. If there isn't one you can get one done at a cost of around £50-100. Thing is it won't show up if there is a boiler issue which it may well be if the house is not getting above 21 degrees. If the house has cavity walls, getting cavity wall insulation is easy, non invasive and fairly cheap and will make a huge difference. If its a solid wall look at insulating wall lining which I've been told makes a big difference. If it's on the top floor make sure your loft is well insulated.

If you have one of those thermostats that you can take off the wall, put it in your coldest room. It will come on sooner and more often giving a better overall background temperature.

Is the ground floor flat occupied? I lived in a first floor flat and when the heating was on in the flat below it was lovely and warm. Sometimes the ground floor flat was empty over the winter and when that wasn't being heated mine was much harder to keep warm.

Damp, boiler needs replacing, radiators of inadequate size/clogged up if they're old. The level of insulation in the roof would also have an impact but may not be under your control. What type of building it is - single skin, stone, cavity wall etc. will also have an impact.

Most UK housing stock leaks like a sieve but you can still heat it to 21 plus using a gas boiler, so although you will almost certainly have draughts and suboptimal insulation there's probably something else going on. Either the thermostat is not reading the correct temperature so turning off well before 21, or there is damp.

Get an infrared thermometer for about a tenner. Take lots of temperature readings around your flat and you will find the cold spots where all the heat is being lost. If it's a wall it's probably damp.

It doesn’t make any difference. It won’t go above 21.

your radiators are then probably too small for the volume of your room

Agree.

This is so true. I'm in a first floor flat and a nice very elderly lady lives underneath and I can absolutely tell when her heating is on 😀

Mine is like this.

Its the seals on the windows of nearly every room which I dont have the money to fix.

What is your thermostat set to? Does it make any difference what the weather is like outside - it's really cold at the moment but when it was warmer and you had the heating on and the thermostat set above 21 could you get it above this temperature?

Does adjusting the thermostat down or up actually turn the boiler on or off? It's currently 18 degrees, my thermostat is set to 18 and so the boiler is off. If I turn the thermostat up to 19 then the boiler clicks on. If I turn the thermostat down then the boiler turns off. Does yours?

What flow temperature is the boiler set to?

I can set my thermostat to 25, it’ll still never go above 21.5 max.
Tbe thermostat does work, so if I set it to 20, it’ll click off when it reaches 20 and lock back in as it drops off. But if I set it to 22 it’ll just stay permanently on as it’s not able to reach that temperature.

I’ve turned the boiler up to 75 I think.

I used to have the thermostat in the coldest room but have had it in the warmer living room recently. In the colder rooms it’ll struggle to get above 19 and would still feel freezing in there.

I just felt my bedroom radiator and there does appear to be cold spots as people have suggested but they haven’t been on long so I’ll try again in a bit. I also think I could do with bigger radiators.

21 isn't cold

C rating apparently