House Slow to Warm Up
Discussion
I've been playing around with some of the output available from our new Hive thermostat to try and understand why our house is slow to warm up once the heating comes on:
As the above shows, the temp drops very slowly once the heating goes off at 8:30am until it comes back on at 2:30 (drop of 0.9 degrees), however it then takes ages to warm up to the set temperature.
Am I right to presume that the slow reduction when the heating is off makes insulation / heat leakage less likely to be the cause?
I'm beginning to think I need to measure and size my radiators to make sure they are sufficient for the rooms.
Am I missing anything?
As the above shows, the temp drops very slowly once the heating goes off at 8:30am until it comes back on at 2:30 (drop of 0.9 degrees), however it then takes ages to warm up to the set temperature.
Am I right to presume that the slow reduction when the heating is off makes insulation / heat leakage less likely to be the cause?
I'm beginning to think I need to measure and size my radiators to make sure they are sufficient for the rooms.
Am I missing anything?
What size rads do you have ?
My house takes approx 15 mins to warm up as I oversized the rads - ie 3mx3m bedroom has 1800x600 rad (with convector)
With smaller rads you can increase the temp from the boiler (but that is less efficient) adding silver "bubble wrap" behind them will help a little too.
My house takes approx 15 mins to warm up as I oversized the rads - ie 3mx3m bedroom has 1800x600 rad (with convector)
With smaller rads you can increase the temp from the boiler (but that is less efficient) adding silver "bubble wrap" behind them will help a little too.
Do the radiators need bleeding? Do they get hot all over?
I was always disappointed with the heating in my house until I realised that the radiators were all only half full!
Once that was sorted the difference was huge. An obvious one I know but worth checking.
Make sure also that the system isn't gunged up, especially important if you have microbore pipes.
I was always disappointed with the heating in my house until I realised that the radiators were all only half full!
Once that was sorted the difference was huge. An obvious one I know but worth checking.
Make sure also that the system isn't gunged up, especially important if you have microbore pipes.
My house is similar, takes an age to warm up and never feels "cosy" unless the heating is on for ages. Once it's up to temp it does seem to cool down slowly. The stats below are from a particularly cold day last year:
What type of boiler do you have? In my relatively modern house I have a system boiler and found that the automatic bypass valve was either faulty or wasn't set correctly, so water was being returned to the boiler too hot and it was short-cycling. Performance has improved slightly since replacing the valve but still not happy with it. I suspect my radiators are undersized but I haven't got round to measuring them and calculating the current/desired amount of BTU for each room.
What type of boiler do you have? In my relatively modern house I have a system boiler and found that the automatic bypass valve was either faulty or wasn't set correctly, so water was being returned to the boiler too hot and it was short-cycling. Performance has improved slightly since replacing the valve but still not happy with it. I suspect my radiators are undersized but I haven't got round to measuring them and calculating the current/desired amount of BTU for each room.
Simpo Two said:
In the photographic world we call this 'measurebating'.
Just put the TV on and get on with life
Just put the TV on and get on with life
I'm glad I don't have Hive. I get obsessed enough about things that I can already measure. MPG, for instance, it's not like I need to be careful of my expenditure (being a PBCD) but I find it unnecessarily interesting; never used to when I had cars that didn't indicate this. It's also why I don't have a water meter. I'd just not wash to reduce my usage.
chris.tarry85 said:
It's a 60's house with a 90's extension.
Radiators are bled and hot, although some are on microbes piping which is not ideal.
Combi boiler so flow temp set to condense, some radiators are single panel so not a good combination.
If your heating was designed to be run at higher water temps than the boiler produces in condensing mode, then the rads will be warm not hot, and it will take a long time to warm up the house.Radiators are bled and hot, although some are on microbes piping which is not ideal.
Combi boiler so flow temp set to condense, some radiators are single panel so not a good combination.
I bet the OPs gas bill is tiny!
Get the flow temp whacked up. Condensing only works if the rads have been sized with it in mind, although older properties did tend to have biggish radiators so that work out OK when swapping an old boiler for a new one.
One of my daughters had the whole system replaced in her 1970 house - the WB accredited fitter spec’d tiny rads. I got them to fit larger ones but I’m sure they thought I was an arse. They set the boiler on max and looked gobsmacked when I pointed out the instruction say set on 1-2 (out of 6). Her house gets warm in minutes.
Get the flow temp whacked up. Condensing only works if the rads have been sized with it in mind, although older properties did tend to have biggish radiators so that work out OK when swapping an old boiler for a new one.
One of my daughters had the whole system replaced in her 1970 house - the WB accredited fitter spec’d tiny rads. I got them to fit larger ones but I’m sure they thought I was an arse. They set the boiler on max and looked gobsmacked when I pointed out the instruction say set on 1-2 (out of 6). Her house gets warm in minutes.
Edited by Sheepshanks on Tuesday 23 January 09:45
V8RX7 said:
What size rads do you have ?
My house takes approx 15 mins to warm up as I oversized the rads - ie 3mx3m bedroom has 1800x600 rad (with convector)
With smaller rads you can increase the temp from the boiler (but that is less efficient) adding silver "bubble wrap" behind them will help a little too.
Always best to fit the biggest doubles that will will fit, it will save money in the long run. You can always turn a double down but you can't turn a single up. When I did my loft I was determined for it not to be cold so fittted massive twin doubles. Have you balanced the system? My house takes approx 15 mins to warm up as I oversized the rads - ie 3mx3m bedroom has 1800x600 rad (with convector)
With smaller rads you can increase the temp from the boiler (but that is less efficient) adding silver "bubble wrap" behind them will help a little too.
chris.tarry85 said:
I think the next step will be to replace some of the single panel radiators with doubles.
Just be careful on the sizes if you're wedded to the idea of low flow temps to keep in condensing mode. Radiators are usually rated at 75C flow temp. The boiler needs water coming back at less than 57C to condense.Gassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff