Are my radiators too small?

[RadiatorBTUQ]

OK, not me but my brother 😂. He's just moved into a new house and it's cost them £80 this week in gas and electric when they are used to spending half that in a slightly larger property. ...

We're trying to work out of whether the radiators may be insufficient for the space, so the boiler is struggling to heat the house and working overtime.

Does anyone have an idea on how to work out the BTU of a radiator that's already fitted? So we can calculate whether they are up to the task!

Could you look up the make model and size ( or Google image search) it should say in the details.

If they literally moved this week did they give an accurate meter reading on move in day? Could just be a billing mix up?

Alternatively is the house insulated properly, or does it have more external walls than the previous property? Are the windows bigger/single glazed ets? Could be that it's not holding heat well.

Theres a formula to use to calculate the size of radiator for a space, BTU is the metric

BTU Calculator | Radiator Calculator | Simple Heat Calculator https://share.google/Bo9mYHgfiZ7sYgx5R

There could be lots of reasons for the higher bill and if the house is warm enough with the heating on for a similar number of hours a day, the radiators are probably the correct size. More likely the walls in the new rental are single brick rather than cavity / there's a gap under the house and cold air is making the ground floor rooms cold / the windows or the roof provide less insulation / this property is open plan with no hall rather than having doors to prevent drafts and warm air rising up the stairs, or it has hard floor instead or carpets. Hopefully there will be ways of making it cosier.

OP, have a look at the EPC report for the new rental. There should be one on the agent's site if it was rented through an agency, or you can google 'find an EPC' and look at the report by typing in the postcode. It will say which aspects of the building are energy efficient and which are not.

Are the thermostatic valves turned up to the max and rads bled?
If so, are the rads getting hot all over?

It's the smart meter that's reading so high, they can see the daily use. But yes to readings supplied.

Insulation believed to be good, but they'll check the loft this week. Similar amount of glass, same external walls.

I think it'll have to be reverse image search but they seem pretty generic to me!

Yes we know, but we don't know what the BTU capabilities are of the existing radiators....

They've bought it, not rented.

I've asked what the EPC suggested but in my experience the only improvements they ever suggest are things like LED light bulbs.... It's a modern house with fairly new double glazed windows etc.

Yes and yes. My suspicion is they aren't powerful enough, so are fighting to heat the house all day.

You can guesstimate it from the surface area of the radiator. So is it single or double fin and what measurement.

when was the boiler last serviced and is it powerful enough for the job?

Sorry, don't know why I thought it was a rental.
If the problem persists, there is a free service in some areas where volunteers will come round with a thermal imaging camera and identify any cold spots. In a new build estate near me the area under the bay windows was losing a lot of heat. It was easy and cheap to fix. Seems that although some new housing is much better insulated than older homes, some is quite poor.

There's also the Cold To Cosy service in some areas which is very helpful.

Seems to be a mixture of styles, shapes and sizes actually. A couple of cast iron column style ones which are probably up to the job, but several look to be single fin "flat panel" but searching around suggests that style have a much higher BTU than I would have given them credit for 😂.

Hi
so not sure if this will be helpful - but we had similar issue and we had air in radiators so we 'bled ' them. Not sure if that was issue

Is it a new build? If so you might be signed up to a rip off provider by your lovely developer

No, not a new build but will remind them to check who the provider is!

It's a perfectly reasonable question. When we bought we changed radiators because the ones that were there were absolute not enough. I just used few google BTU calculators to figure out the room need and what is most likely the radiator output (searched as similar as possible rads on screwfix and b&q).
I still don't understand who thought that 600x1200mm basic single panel rad is enough for 5x3.5 room..... "professionals" 😂🙄. We switched to correct sizes and added one in living space and it was glorious.

A number of things you can check - I don't know the type of system so not all might apply but here goes - bleeding radiators and what colour is the water, are the radiators blocked with sludge and has the system had a product such as fernox added, is the pump working - they can block with sludge and then fail to turn and may need replacing (still get some heat) - thermostats actually working and how old. There's a device that can see the heat in pipes / floor / radiators to see their efficiency and you can even (in some systems) use a magnet in the appropriate area of your system externally, which doesn't stick to the pipe but will the area if there's a sludge blockage / buildup (radiators loose bits of their internal body over time). Boilers have specifications should should know if OK for the number of rads. Lots to check, including boiler servicing and settings.

The tall narrow column radiators are generally less effective than traditional ones. They look trendier but they aren't as good!

Changing from single to double fin can make a big difference.

If the radiators are to small, or the boiler is not big enough the house will never get warm. There's is a lot of heat going in, so it must be going somewhere. Poor insulation and badly fitting windows/doors is the most likely cause, or it's set to heat the house at the wrong time, don't have the stat at 20C overnight when you're in bed, or during the day if the house in unoccupied. You can't really compare fuel costs, you need to know how much energy you are using in KWH to make a comparison, there is always a chance, of course, that you're on a particularly crap tariff or that you have an electric boiler or an air source heat pump, both of which are more expensive to operate than gas.

I'm a spark, but do a fair bit of heating work with the plumbing fraternity, there are lots of variables.

Wall construction
Roof insulation
Floor insulation (often none on old properties)

Are the rads double or single panel, and do they have fins
Is the system 1 pipe or 2 pipe
Is it gravity or pressurised
Is it a combi boiler or a conventional boiler
Is there a calorifier (hot water tank) in the system
Is there a zone control system (S or Y plan)
Do the rads have thermostatic valves
Is the main thermostat correctly located

Check the hot water temp on boiler - if you need to ask cold when running a bath it’s set too high , people often overlook this and it’s a waste of £££’s over heating hot water