# Stove and Boiler Capacity for a New Build



## BMD (11 May 2011)

Hi,

I am building a well insulated house, airtight and I am installing two solid fuel stoves (one with a back boiler, the other without) and I am looking for information on the required capacity I need for these two stoves.

Stove with Back Boiler
This will be going into a room that is 6.45 m x 5.4m with a vaulted ceiling bringing the volume of the room to 115m3. It will be supplying a 500L buffer tank. I want to know how many kW or BTU's I need for the room and the same for the boiler?

Stove without back boiler
This will be going into a room that is 5.4 x 5.4 m and has 9ft (2.8m) ceilings giving a volume of 82m3. Again I want to know how many BTUs or kW I need for this room

Any help would be appreciated


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## Trilogy 1982 (11 May 2011)

To properly calculate the heat losses for the rooms we would need to know U values for walls, vaulted ceiling, no. of windows etc so these are only ball park figures.

For the boiler stove, if you are using a 500l buffer then the output to water of the stove should be no more than 10-12kW. You want about 40l of water storage for every 1kw of rated boiler output.  Around 4-6kw should be plenty for the room output. 

For the standard stove around 3-4kw would be plenty but finding a nice generous looking stove with such a small output could prove problematic.

Another problem you will face is down to the airtightness factor.  You will need to purchase a room sealed stove and your choice will be more limited and models more expensive. It will need to be room sealed not just with an option of a ducted air supply.


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## threebedsemi (11 May 2011)

As Trilogy has posted, you don't offer enough info about your build to be able to advise on the exact spec for boilers for your house.
If you are building a new house, you will be required to obtain a BER certificate for it. The best route to take is to:
1. Appoint a BRE consultant who is experienced with low energy, highly insulated houses.
2. Get the consultant to prepare a preliminary BER cert based on the specs you hope to achieve with regard to insulation levels, airtightness etc. This involves the consultant inputting the specs for different elements into the software and calculating the end result. 
3. This preliminary cert will tell you, amongst other things, what your heat load for the house is going to be. You can then work out what size boilers you need to meet this heat load.
4. It is pretty easy to examine different options with regard to insulation levels etc. once the basic info has been inputted into the software. You should take the opportunity to examine different options for the insulation levels of elements, what savings different solar hot water options will give you, is it worth using triple glazing in certain areas, etc.

It is important to note that the heating/hot water/airtightness aspects of a house are interrelated, and a good consultant will be able to advise you on the most efficient way to go about obtaining your required results.


www.studioplustwo.com


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## SINED (8 Feb 2013)

HI BMD 
Did you install the stove have you found it successful heating rads and water  I am also going down the same road as you,,,Thanks Sined


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