Boiler sizing

[Frankom]

Hi All,

Apologies as firstly I'm no heating engineer but I have a basic question regarding boiler sizing in kW terms.

I have a heating demand (from an Energy Performance Certificate) of 36,000 (heating) and 3,000 (hot water).

What is the calculation I apply to correctly size the boiler in kW terms?

Many thanks in advance

 

[Howsie]

Welcome.

Your engineer will work this out for you based on your setup.

 

[Frankom]

Hi thanks for your response. I understand that the engineer can work it out and the calculation is exactly what I am after.

Many thanks,

 

[kirkgas]

Hi All,

Apologies as firstly I'm no heating engineer but I have a basic question regarding boiler sizing in kW terms.

I have a heating demand (from an Energy Performance Certificate) of 36,000 (heating) and 3,000 (hot water).

What is the calculation I apply to correctly size the boiler in kW terms?

Many thanks in advance

If these figures are btu's then you divide by 3412 to get KW, but to be honest it will be beneficial to discuss your requirements with whoever is going to do the job

 

[Reg Man]

Boiler sizing, is determined from the whole house heat loss calculation, under part L building regulations. In summary you calculate the heat loss from the building constructions to establish what size boiler you require.

 

[Ermintrude]

Nonsense! It's based on which boiler is on offer? Didn't ray have a 49kw LPG going cheap..... That's perfect size.

 

[Killy Bing]

Nonsense! It's based on which boiler is on offer? Didn't ray have a 49kw LPG going cheap..... That's perfect size.

37 cdi.

sat in a caravan right now toasting it :devil:

 

[Ermintrude]

New trims for caravan soon then? All melted plastic?

 

[Frankom]

Hi All,

Thanks for your responses, caravans aside :28: does anyone have the calculation?

The sums stated are kWh usage so i need to convert 39,000 kWh usage to establish the correct boiler size. Do I divide this sum by the estimated hours per day usage?

I just want an idea as Im moving into this house and want an indication of size to get price comparisons and choose the right boiler technology Biomass/Oil/heat pump

Please help........................

 

[doitmyself]

I have a heating demand (from an Energy Performance Certificate) of 36,000 (heating) and 3,000 (hot water).

Does the EPC say the following:

Space Heating (kWh per year) =36000;
Water Heating (kWh per year) = 3000?

If so that is just an estimate of how much fuel you will consume in a year; it has nothing to do with the size boiler you need.

The actual boiler size will depend on the calculated heat loss and how you heat the hot water - combi boiler (instant HW) or HW cylinder.

You can find out the size boiler needed if you have a HW cylinder by using Whole House Boiler Size Calculator.

A combi boiler will have a higher output, which depends on the incoming cold water flow rate.

 

[lame plumber]

Dont even bother to go by an EPC reading, the muppets who do these tickets often dont know their arse from their elbow. Reason I say this, on one occassion the guy doing an epc on a flat I manage asked what sort of heating warmed the place, when his backside was sat on a electric night storage heater, he wondered where the pipes where????? Another one doing an EPC on my own place when I put it up for sale had never seen an AGA before and wondered where the control knobs were for the hot plates !! . Your engineer will work it out for you, get him to explain how he gets the figures if you dont trust him.

 

[Reg Man]

Trouble with EPC is not all surveyors are fully experienced for the task in hand. But to make things worse the system for it is not up to date with technology either. So lets not give these surveyor's to much of a hard time. One example is, air source and ground source heat pumps. The system In place is still caching up, as these weren't even listed

 

[lame plumber]

neither are AGAs or other range cookers, underfloor insulation or insulation in roof spaces they cant see or get to. Basically, EPCs are a farce, but thats government for you, only getting it half right, never perfect!

 

[Reg Man]

Also the finer detail. Minimum 250mm rockwool in the loft? No I have vaulted ceiling with 150mm celotex board as insulation. Which is more efficient?

 

[Frankom]

Thanks all. I really appreciate your advice, i'll measure the house and use the link provided for the sizing.

:smoking: