How long does it take for your house to heat up?

ilikecookies

I realise that there are a lot of variables which will affect the speed at which a home will heat up (eg. size of the rads, boiler power & temperature setting, location of room stat, levels of insulation, etc etc) but I am curious to hear from others.

For context we live in a 1930s 5-bed house. It's double-glazed and in quite an exposed location with the obvious insulation measures already taken (ie. loft insulation, cavity wall insulation, etc).

On paper at least I think the boiler and rads are correctly sized but the heat-up time still seems rather slow. On average from a cold switch-on it takes about an hour to raise the temperature by 1 degree and around 45 minutes per degree after that.

I wondered:

1) Is a design principle which says in theory a system should be sized to raise the temperate by x number of degrees per hour. Googled but haven't found anything specific on this.

2) What sort of times it takes to warm up your house

Hoping with the info I can then look at how to/if to make some changes.

Swipe

What temp are you heating it from?

HappyMJ

ilikecookies wrote: »

I realise that there are a lot of variables which will affect the speed at which a home will heat up (eg. size of the rads, boiler power & temperature setting, location of room stat, levels of insulation, etc etc) but I am curious to hear from others.

For context we live in a 1930s 5-bed house. It's double-glazed and in quite an exposed location with the obvious insulation measures already taken (ie. loft insulation, cavity wall insulation, etc).

On paper at least I think the boiler and rads are correctly sized but the heat-up time still seems rather slow. On average from a cold switch-on it takes about an hour to raise the temperature by 1 degree and around 45 minutes per degree after that.

I wondered:

1) Is a design principle which says in theory a system should be sized to raise the temperate by x number of degrees per hour. Googled but haven't found anything specific on this.

2) What sort of times it takes to warm up your house

Hoping with the info I can then look at how to/if to make some changes.

1 degree every 45 minutes....that's awful... It takes my house not much more than 30 minutes to increase in temperature by 10 degrees. From an overnight low of 8 degrees inside (and an outdoor temperature of 2 degrees) at 6.30am to 18 degrees at 7am. If I want it warmer it does take quite a bit longer to get to 19 then even longer to get to 20, 21, 22, 23 and 24 then almost forever if ever to get to 25 as the heat loss from the house is being matched by the maximum output of the boiler of 11.72kW. There's a few notes to add...the bedrooms are set to a low temperature...12 degrees...I don't like warm bedrooms so most of the output of the boiler is being output using just a few radiators in the entrance, lounge, dining room, downstairs wc and bathroom.

Ectophile

I don't think my central heating does much better than that. Most of my radiators are on microbore pipes, so the radiators take a long time to heat up to their full temperature. They are also rather old radiators that don't have all the fins on like modern ones do.

SEE

20 to 30 mins for a full hot water tank, 4 very hot radiators and a very warm room in which the stove stands. This is continuous on filling stove every 3 to 4 hours. I use coal last thing at night to keep it ticking over until the morning as I can't really afford coal for full use any more.

shegar

My thermostat for overnight is set to 13 degrees, at 5.30 every morning it comes on at 21 degrees and it reaches that temp in half hour......GCH 9 rads, newish boiler........

10 inches loft insulation, double glazing, we have a porch on the front of bungalow, so 2 doors to get into the hall, and same on back door , so we have no draughts.........

I have a open fire which I light every evening and then turn the gas off, it keeps the one room nice and very cosy, burn few large lumps coal and couple logs, so its quite cheap..........................And a nice cuppa tea while watching the flames...:D

ilikecookies

Thanks to all for the responses.

HappyMH - 10 degrees in 30 mins - wowzer! I suspected my system was slow but thought the average would be more like a 3-5 degree increase an hour. I understand that theoretically a system could be specced to do 30 degrees in 30 mins if the boiler and rads are big enough but of course there is usually a trade off with efficiency and installation cost in terms of sizing the boiler.

I guess the follow-on question is what your heatloss is like? For example, if it only takes 30 mins to raise the temperate this far I would imagine you don't use that much gas relatively speaking. For example, you have a big surge of use in the first 30 mins to raise the temperate 10 degrees and then after that assuming your heat losses are low it really shouldn't take much to maintain that temperature? I guess maybe you are a little unusual though in the sense that you are only really heating the downstairs?

Swipe - As regards the temperature I am heating from a bit of content may help. At present I have the heating on for 2 hours in the morning and 2 hours in the evening. I'm not up in the morning to see what the start temperature is but by the end of the morning cycle @ 07.30 the stat reaches the setpoint (19.5 degrees). Even with this cold whether when the heating comes on again at 17.30 the stat has fallen to 17.5/18 degrees. I *think* this is probably a fairly low rate of heat loss though the stat is in the hall and I suspect temperatures in other rooms may have fallen a bit more.

Ectophile - I feel your pain Luckily we only have one rad on microbore and that is definitely much slower to heat up than the rest. Our rads do have fins though which I understand make a fair bit of difference. I don't think they make single convectors without fins any more so yours must be fairly old I think?

shegar - thanks for sharing. Our front door currently opens into an internal porch area which in turn opens into the hall (where the thermostat is). This is obviously a problem as once the front door is opened so much cold air enters the house. I'm definitely going to look into having another set of internal door fitted to block off the porch from the hall.

SEE - we are blessed with a stove which means we can keep one room toasty in the evening when the rads have gone off!

Ectophile

The central heating system was installed before I moved in. But I do know that it's a reasonably modern condensing boiler retro-fitted to an existing central heating system.

I had the wood burner going this evening. It was so cold and windy outside that the central heating took about 4 hours to warm the house by 6 degrees C today.

SEE

Ectophile wrote: »

The central heating system was installed before I moved in. But I do know that it's a reasonably modern condensing boiler retro-fitted to an existing central heating system.

I had the wood burner going this evening. It was so cold and windy outside that the central heating took about 4 hours to warm the house by 6 degrees C today.

4hrs!!!!

Goodness me, have you got good draught excluders and heavy curtains? My house is old and draughty and single glazed. I can't bear to rip the stained glass out and replace it with double glazing I have draught brushes on the bottom of every door and heavy curtains front and back as well as on the front door and back door. Those portier? curtain rods are very useful. They lift up out of the way when you open the door.

macman

The big variable here is the ambient temp, since heat loss increases with a greater differential between the two.
The warmer you make your house, and the colder it is outside, the faster it will lose heat.
It's not just about increasing the internal temp by 1C in a hour or whatever. Your calculation makes no allowance for the variable rate of heat loss.
In the current weather, achieving that 1C rise will take longer, due to the higher losses.

Ectophile

I think the main problem is that the radiators aren't well suited to a modern condensing boiler. Condensing boilers are meant to be run at a lower temperature so that the condensing bit works properly. But the radiators are the old-fashioned flat panels that don't have all the cooling vanes that the modern ones have.

To make it worse, all but one of the radiators is connected using microbore pipes. As a result, the radiators take about 1/2 hour just to reach working temperature.