How many Killo watt calculations do I need please

[bigcol]

I’m about to make a desision on a liquid heater 5kw or 9 kw but would like to know what will be best

I have been using a webasto 5k, but I’ve given up, I’ve added another rad

so i have now

I have 1 x colarifier
2 x double rads 600 x 1.4 lenght
3 x 600 x 500 singles

I’ve heard that there are calculations, I’ve tried to find somthing on google

please help me if anyone can?

Thank you in advance

Edited March 31 by bigcol

[Jen-in-Wellies]

Not a heating engineer, but my understanding.

Ignore the caulflower. Once it is up to temperature, it takes no more heat from the heater.

Find the specifications for your radiators. If not available, then use near equivalent. Eg, Screwfix 600x1400mm double rad, gives a heat output of 8165btu. <pedant>Btu (energy) should actually read btu/hr (power). </pedant>

Add them all up, then convert from btu/hr to kW by dividing by 3412. One of the radiators above uses 2.4kW, for example.

[BEngo]

Wot Jen said.  Also look at radiator makers sites e.g. Stelrad and Myson

Radiator heat output is affected by size, number of panels and the finning arrangements.  Single rads  have 1 or no fins, double rads 0, 1 or 2 fins.  Each set  of fins increases the ouput a bit.

 

N

 

[bigcol]

Thank you Jen

and saved some money

just proves that this site works!!!

 

after being told to get a bigger heater. Tut!

 

col

[David Mack]

2 hours ago, Jen-in-Wellies said:

Not a heating engineer, but my understanding.

Ignore the caulflower. Once it is up to temperature, it takes no more heat from the heater.

Find the specifications for your radiators. If not available, then use near equivalent. Eg, Screwfix 600x1400mm double rad, gives a heat output of 8165btu. <pedant>Btu (energy) should actually read btu/hr (power). </pedant>

Add them all up, then convert from btu/hr to kW by dividing by 3412. One of the radiators above uses 2.4kW, for example.

That calculation tells you what heat output the radiators can produce (at the water temperatures assumed by the radiator manufacturer). It doesn't tell you whether that heat output is sufficient to keep the boat warm, which depends upon the boat size, how well insulated it is, level of ventilation, single or double glazed windows etc.

[cuthound]

Try this to calculate kW ratings of radiators.

 

https://www.simplifydiy.com/plumbing-and-heating/radiators/power