How many BTUs do I need as extra

[Jacka]

Hi all

A very quick question.

Just about to order some new radiators and wanted to know how many BTUs over the calculators should I go for. Some one told me to go 10% recently, but when I had a new central heating system in another property (10 years ago) the plumber told me to double what I need.

Any help would be appreciated

Thanks

Jacka

 

[Agile]

Radiators have been rated in kW since about 1982 when the country was metricated.

You have told us nothing about your boiler or what heat ratings you have chosen the radiator sizes on.

Rads can be oversized and this can speed warm up times and sometimes improve boiler efficiency.

But it is very foolish to fit undersized rads.

I like to choose rad sizes which fit neatly into the available spaces and to use single panel where possible as that gives a more distributed heat input into the room.

Its good to oversize by about 20% compared with calculated sizes if the cost is immaterial. But builders and competitive quotes will give exact sizes for financial reasons which I always think is a pity but will obviously happen when people want to spend the least possible.

Tony

 

[45yearsagasman]

Deleted

 

[Jacka]

Cheers Tony

I bascially have one bedroom that gets quite cold in the winter as we have redicoulous large windows about 6m2 (1960s build). I also have another carpet up in bedroom Two so I'm taking the opportunity to change that rad for a metric one.

Bedroom one 360 x 330 x 225
BTUs required approx 2500 - 3000 (According to BTU Calc)
Going to replace the single rad with a single metric convector (Myson Select) 600 x 1300 (approx 4k BTUs)


Bedroom two 240 x 260 x 225
BTUs Required 1500 - 2000 (According to a BTU Calc)
Going to replace the single rad with a single metric convector (Myson Select) 600 x 1300 (approx 3.5k BTUs)

I know the smaller room will be fine as it's double, but just wanted to see how much I should over compensate in Bedroom One

Cheers

Jacka

 

[Jacka]

Do you also think this will help with boiler efficiency as it will heat the room quicker?

 

[Agile]

Sorry I have always worked in kW and BTU are some kind of old fashioned thing from the days of steam power.

I am sure my grandfather would have known about them though as he worked at Poole coal fired power station!

 

[Jacka]

I had no idea, I wonder why these but calcs are still used. I may have to review my calcs in KW

 

[Jacka]

Rad for bedroom one would be 1253 watts ( 3.6x3.3x2.25)

Rad for bedroom two would be 1063 watts (2.6x2.4x2.25)

Isn't that just a few light bulbs. I think I'm going to need a double panel plus rad for bedroom 1

 

[Agile]

Those are very small rads!

I always advise using single panel because the longer length spreads the heat more evenly.

Tony

 

[FiremanT]

3412.142 BTU per Kw
Kilowatts to BTU/hr conversion table
Power (kW) Power (BTU/hr)
1 kW 3412.142 BTU/hr
10 kW 34121.420 BTU/hr
100 kW 341214.200 BTU/hr
1000 kW 3412142.000 BTU/hr
1 more row
Kilowatts (kW) to BTU/hr conversion calculator

 

[Jacka]

So how many KW should I be aiming for with the room size I have?

 

[Jacka]

Do you think a double panel plus in bedroom one would be better?

 

[Agile]

As I said above I prefer single panels as they distribute the heat better.

Those sizes are about right but I would suggest about 20% larger.

A very simple way is to check at 100w per sq meter for a well insulated room with only one external wall an 200w per sq meter for a less well insulated room with two external walls ( or more ).

Tony

 

[Agile]

Normally single panel are cheaper at £ per kW.

Tony