Radiator sizes for full house heating

[danieljephcott]

Hello all,

Im new to the site and I have one question of many im sure.

Ive just bought my first house which is need of a total make over.

The house is having the following done.

Air central heating ripped out and replaced with combi boiler and rads.
New kitchen
New bathroom
A ton of plastering
All new flooring
Complete decorating
Full re wire
Lots of additional lights etc.

Anyway my first question I have is regarding the radiators and the sizes.

We are just getting all the pipework in at the moment which we are using the JG speed fit plastic pipeing.

Best offer on rads I have is Screwfix Kudox type 22 double panel compact radiators. The boiler which is being fitted is an alpha intec 28kw combi. Possibly going slightly larger but doubt I need it.

The house its self is a semi detached two bed with an attached garage. It’s a standard 1970’s brick house with tile roof. The house has 6 year old double glazing and a upvc double glazed front door and sliding back door.

Heres what size radiators im wanting to fit. Just for reference the ceilings are 2.4m high.
All rads minus the hall will be fitted with Danfoss RAS-C2 trv with lock shields.

Hall – 1.75m x 2m
Rad: 500mm high x 400mm wide
2044 BTU


Lounge – 5m x 3m
Rad: 500mm high x 1600mm wide
8347 BTU


Bedroom 1 – 3m x 2.5m
Rad: 500mm high x 600mm wide – fitted under the window
3064 BTU


Bedroom 2 – 3m x 2.5m
Rad: 500mm high x 600mm wide – fitted under the window
3064 BTU


Bathroom – white flat towel rad 700mm high x 400mm wide
884 BTU


Just wondering how they look? Wanting to order some asap so just wanted to check the sizes.

thanks

dan

 

[mogget]

Try the heat loss calculator http://www.plumbnation.co.uk/heating-calculator.php

And the Stelrad Elite catalogue http://www.stelrad.com/uk/docs/elite_technical_info.pdf, other brands will have similar outputs

Probably best to work in Watts rather than BTU's these days.

The catalogue lists for 75/65 degree flow and return temperatures. It may be worth oversizing the rads by 20% to use 65/55 degrees so your boiler can condense more often (increases efficiency and helps in a really cold winter too).

Hope that helps.

 

[danieljephcott]

i used the btu cacluator and all rads are atleast 1000 btu more apart from hall and bathroom which are just a little more.

there are no watt information on the screwfix website which is a pain.

using the calculator you provide the following rooms need:

hall - 561 watts and 1914 BTU rad ive selected is 611 watts and 2087 BTU

Lounge - Needed: 1904 watts and 6496 BTU: rad ive selected is 2445watts and 8347 btu

Bedroom 1 and 2 - 1018 Watts and 3473 BTU - think i need to up to a 500mm high x 800 wide which is 1223watts and 4173 BTU

Bathroom - this is coming up saying i need 813 watts and 2773 BTU but to put a towel rad in big enough itll need to be like 500mm wide x 1500 high. thats huge. do bathrooms work the same?

 

[mogget]

Bathroom - this is coming up saying i need 813 watts and 2773 BTU but to put a towel rad in big enough itll need to be like 500mm wide x 1500 high. thats huge. do bathrooms work the same?

Hi, bathrooms do work the same but as you've noticed towel rads tend to have a lower output size for size.

It's worth bearing in mind though that each room of the house cannot be considered in isolation. Heat will always flow from one room to the next especially if doors are open etc. So unless your bathroom is particularly cold you'll probably be ok.

It's a good idea to oversize (slightly) the rads with TRV's. If the rad nearest the room stat is oversized but the ones with TRV's are marginal then those rooms would never get hot enough for the TRVs to kick in.

 

[danieljephcott]

the thermostat will be in the hall which has the smallest radiator so that shouldnt be a problem.

so looking at things the radiators i have selected (bedrooms made slightly longer) are ok.

 

[Whitespirit66]

Bathroom - this is coming up saying i need 813 watts and 2773 BTU but to put a towel rad in big enough itll need to be like 500mm wide x 1500 high. thats huge. do bathrooms work the same?

Towel rails are only really any good at warming towels, not very efficient at space heating. TRy looking for high output versions, but unless your bathroom is very small, you are likely to need something sizeable.

 

[danieljephcott]

bathroom is tiny and i over sized on above email.

the bathroom squared would be 3m x 1.8m but one of the corners is taken up from the airing cupboard in the landing and that cuts into the room by about 1mx1m in one corner.

 

[Whitespirit66]

As said above, you will gain some heat from elsewhere in the house. This varies to some degree on the layout of your house.

Remember that when it's covered in wet towels, any towel rad's output will be reduced. If it's a little oversized, you can reduce output with a TRV. If it's under, then you're stuck.

 

[halfway]

I would advise installing a neat looking towel rail and a small radiator also. It would cost very little extra. You could always turn down your TRV on the radiator if you thought you were getting too much heat there, or even better, put one of these http://www.heatingcontrolsonline.co...mp-i35-horizontal-programmable-trv-p-671.html on it. Then you could have the bathroom nice and warm when you have a bath or shower and let the towel rail keep it warmish at other times.