Radiators not up to the job

[Hogan]

We recently moved into a new build house and are finding that the lounge is freezing!

I think there may be two issues but wanted some opinions.

The main thing, I think, is that the two radiators are not large enough - there are two of them, both 900mm by ~450mm and both are single convector types.

I've looked up the BTU outputs for this type of radiator and they seem to give out about 2500 BTU's per hour each.

Our lounge is about 235 sq ft in floor space and from some online tools I've found, it appears that the room requires about ~10000 BTU's.

Does this sound about right? In this case, our radiators could do with beefing up. Is it common for new houses to be equipped like this?

(the room is also north facing with a window and french doors ...)

There's also a vent in the bottom corner of the room, presumably there in case a penguin fancies setting up home there as the draft is incredible! Are these vents necessary? There is no fire, and all the windows have trickle vents ... I'm thinking of covering it up.

I'd be interested to hear some feedback before I start grumbling to the builders

All opinions most welcome.

Thanks in advance.

 

[namsag]

If memory serves me right definition of central heating is the ability of the rads in a room to raise temp to 21 degrees centigrade in an hour if outside temp is minus one.

 

[Fluffster]

Hogan
Block up the vent unless you have a gas fire in the room.
Is the house still under guarantee if so could be in for a claim if it did not meet the buildings regs when built.
Pete

 

[sime10]

If there is not a fire in the room and the boiler is not in adjacent room with vents into the room Block that vent up

 

[Strachan]

You could ask to see the spec on the heating system, the builders should have a copy available. Boiler size and radiator outputs should be on there. If your system doesn`t meet their spec, kick up a stink!

 

[Hogan]

The builders are now looking into it for me - I'll be interested to hear what they come back and say ...

Thanks for the advice !

 

[Steve__M]

Some great suggestions above - speak nicely to the sales advisor to get some of the info as the builder will be less than forthcoming if they think it will involve extra work for them. (Is it a major builder?)

I have 4500 BTU in my dining room which is 2/3 your lounge size (the heating requirements for the two types of room are the same). Extrapolating from this, you'd need 8000 BTU without taking in other aspects of the design.

From experience with a new property, some other things you should try while you're at it.

Check the windows aren't draughty - now's a good time because its cold.
Check that where services come in (gas pipe, electricity tails, extractor fans) that the holes are properly sealed - this is hard to do, but big cold patches on the plaster board are a giveaway, also take sockets off the wall and see if it's draughty behind the plasterboard.

The designers of my system don't take the aspect of the room into account as they design off-plan. But they factored in an extra 20% to account for variability.

Also take anything the builder says with a huge pinch of salt. My house builder tells the most amazing whoppers because they assume the buyer will not have the technical knowledge to argue.

 

[Hogan]

Thanks Steve,

Some good points there - the house was built by one of the biggies (currently the biggest I think ... hint).

I spoke to one of the plumbers the other day and he tried fobbing me off with talk of convection currents etc and curtains interfering with things ... as an engineer, I wasn't too impressed with his theories!

The after sales team are now dealing with it so I'm sure they'll try a similar approach (based on our experience with them to date).