Help me work out why bedroom is so hot!

[DearSisterMichael]

Recently moved into a new house where our main bedroom is north-facing. Having previously had a south-facing bedroom we were looking forward to how cool this would be as DH and I both prefer not to be hot at night. We’ve been in a month now and haven’t had the heating on apart from one day a couple of weeks ago. We’re finding the bedroom unbearably hot though!

The north-facing lounge below our bedroom is decidedly chilly so we can’t work it out. We do have a very old boiler, and the hot water tank is in the next room to us and not very well insulated at all. It could be this and we’re planning on replacing for a combi soon, but do you think that’s it?

Any other ideas? The whole upstairs is pretty warm to be honest, I know heat rises but it’s definitely much warmer than our previous house. Not looking forward to the proper hot weather!

Are there hot water pipes running under the floor, coming from the hot water tank next door?

Check the loft insulation, the roof can act like a giant radiator and radiate heat down.

You possibly just have much better insulation in your new house. Open the loft hatch if you have one and the heat will lessen.

TuxedoJunction there may be pipes leading to the radiator, but the heating has been off so they shouldn’t be on should they?

Daftasabroom and AmbushedByCake1 the loft does seem to have a fair bit of insulation, it looks pretty old though, but maybe that is what’s happening. It will be interesting to see come the winter, we can’t decide when to replace the boiler, it’s a lot of money so maybe better spent on something else if we could somehow sort this problem. We should try leaving the loft hatch open good idea…I’ll try not to get creeped out by how many spiders might come down!

Do you have the windows open?

QuestionableMouse Yes we’ve been opening the windows and might have to resort to a fan which usually we wouldn’t have to do until the height of summer!

Are you keeping the curtains drawn in the day so the sunlight can't warm the room?

HalfShrunkMoreToGo There is no direct sun as it’s north-facing, but also it’s hot in there on days when it’s been just 16 degrees and cloudy. I am thinking we might have to sleep with the curtains open to allow the air in to circulate more, although that will be an early wake up call!

Does the wall adjoining the hot water tank feel warm compared to other walls? It could be that you just need to put an extra layer of lagging on it to stop it from being a low but constant radiator.

BlackAmericanoNoSugar It does sometimes although I’ve not been diligent enough to notice if it’s all the time. Not had a hot water tank before as always had a combi, I take it the boiler will periodically be kicking in to keep the hot water at temperature? As opposed to just when you turn the hot taps on.

Yes, usually the water will be kept hot when the central heating is running. My hot water tank has an automatic electric immersion heater that kicks in if the water isn't heated by the central heating. You might have both an on/off switch by the boiler and a sink/bath switch. In the summertime it's a good idea to keep the switch on sink unless you're planning a bath/shower as it will use less electricity.

I haven’t seen a bath/sink switch so that is something to investigate thanks, does that mean it will keep less water hot in reserve?

We have an old school water tank, our water heats up on a timer set by us. Currently for an hour a day at 7am which gives us enough hot water to last all day. There is also a manual boost button if you need to heat more water that day.

I don’t know much about boilers etc but I would check on what set up you have. We once had a power cut and it reset our timer (I failed to notice), our hot water reverted to an old default timer of between 6am-9pm for god knows how long. My energy bill was super massively effected.

If your boiler and tank is anything like ours, then you should meddle with the timer to see what works for you. We are fine with our water being heated in the morning and it lasts well enough for the two of us but maybe you need it heated for an hour in the morning and then for another hour in the evening for instance?

If your water is in a tank and is heating all day…. I can attest to way more energy consumption that you probably need but I would also hazard a guess at the pipework radiating heat all day when it really doesn’t need to increasing the temperature of the nearby rooms.

Highwind That’s really helpful thank you, looks like we need to investigate when the hot water tank is heating up then. I think we put it on auto so perhaps it’s kicking in during the night when we don’t even need it.

Yes, the sink setting heats just the top of the tank so much less electricity used and from your point of view also less heat emitted.

Get an infrared thermometer and point it at walls, windows, etc this will help you find any particularly warm spots which should help locate the source of heat.

consider the position of the hot water cylinder and the position of the gas boiler. pipes between the two will be hot while the cylinder is being heated.usually under the floor. if you think you know where the pipes are, put a towel over them and feel how hot the floor gets.

photos of your cylinder would be helpful, with its pipes, cables and other devices.

The infrared thermometer is a great idea thanks jimmyhill

Only just seen your reply PigletJohn thank you, I’ve tried to take some pics but it’s a pretty tight fit in the cupboard, let me know if you need to see more.

Do you have a gas boiler? If so, switch off the immersion heater. First, feel the top of the immersion heater cap. Is it surprisingly hot?

Is there something under the red insulating jacket?

There are likely to be two large copper pipes going into the side of the cylinder. How hot are they? Can you see where they go?

Please post photos of them. There may be a fitting on one of them where it goes into the side of the cylinder.

Is the cylinder 18 inches diameter and 42 inches tall?

Thanks PigletJohn, it’s a gas boiler, Ideal Mexico with a Salus digital control/(not sure what you call it).

Under the red jacked is another badly fitting white jacket.

The cap is still v hot, also both pipes going into the top/back are hot, there is one at the bottom front which isn’t too hot.

Those measurements are about right, perhaps more 38ins high

The cylinder is extremely old. The white jacket predates the more recent red one. Red jackets have been around for about 40 years.

Start thinking about replacing it when it starts to leak or some other problem occurs. You can get a modern equivalent which will heat up faster, be much better insulated, and I suggest considerably bigger. The one you have is about 100 litres which is adequate for one bath. You do not have to change to an unvented cylinder, and you would probably need to upgrade your pipes if you did.

I can't see a thermostat or thermostatic valve on your cylinder. This is not unusual on such an old one, but is uneconomical on gas. Probably it heats up all the time the boiler is running, , even if it is already hot enough. This would lead to hot pipes under the floor.

The immersion heater is also very old and is capable of going faulty and overheating the cylinder which can be very dangerous (modern ones have an overheat cutout as well as a thermostat).

Use a thermometer to test hot tapwater temperature.

If you can find a trustworthy independent local heating engineer you could have a new cylinder, fitted with thermostat, converted to fully pumped, with motorised valve and insulated pipes, which would give you better economy and more hot water.

If you want to spend more you could get a new boiler and an unvented cylinder and new water supply pipes, which will be much better, especially if you like multiple baths and powerful showers.

If your house is small with only one bathroom and only one or two occupants, you could have a combi

I would avoid doing anything to your old cylinder because it might leak.

Oh, and if you are having any work done on your CH or HW, get a magnetic filter, such as a Magnaclean, fitted, and learn how to empty out the sludge. An old system is at risk of sludge blockages and it is easier to keep it reasonably clean.

Thanks for your help, it must be the cylinder causing the upstairs to be hot then. It’s been off all night (supposedly) but still hot to the touch.

The jackets should stop much heat escaping, and it will tend to rise in the airing cupboard.

Feel the large pipes going into the side of the cylinder. They should only get hot when the boiler is heating it. Though the upper one will receive heat from the cylinder for a short distance.