Choosing the right heater for the application.
When selecting a portable heating unit to buy it's important to consider all the available options, and the application you are purchasing one for.
Some applications require a very specific heater.
The right method is:-
1. Work out the volume of the area being heated in cubic metres.
2. Choose a 'K' or insluation value for the area - 1 = well insulated house, 4 = poorly insulated marquee or building site.
3. Make a choice as to the temperature rise you are looking to achieve in degrees C. So if you wanted it at 25 degrees, and you thought the coldest ambient temperature you expect to work from was 5 degrees C, you would have to use 20 degrees as the temperature rise figure.
4. Calculate the heating power needed from the information you have gathered using this equation:- (Volume in Cubic Metres) x Temp Rise in C x 4 x Insulation Value (K) = BTU/Hr needed.
5. If you need the output in kW divide the answer by 3412.
When you have the heat energy needed, you have a start, but you still need to choose the right type of heater for the job in hand. There are many factors to consider.
Firstly, if the power required is less than 10,000 BTU or 3kW then a 3kW Electric Fan heater is easily the most sensible choice. The problem you have is if the needed heat is much more than this - adding multiple heaters can take too much power.
You probably only have a 60A ring main at the most, so if you need 5 x 3kW heaters at 13A each, you will be tripping breakers and blowing fuses - pulling 65A!
When the supply is 110v rather than 230v you need a 32A socket per heater. These pull over 20A for every heater.
When you are using a 230v supply, you are limited to 13A per domestic UK plug socket. This equates to 3kW, more and the fuse will blow every time.
The next option is for 3 Phase Electric Fan Heaters. If you need a 9kW heater then a 16A 3 Phase socket can deliver the required heat. If you need up to 22kW you will need a 32A socket. Over 22kW requires a 63A, 3 Phase Socket.
If you don't have three phase electrics, then you really need to consider burning a fuel. The options are really gas or oil. There are various subdivisions in between these, propane, butane, diesel, kerosene - but we'll treat them as two seperate choices.
Cheap to buy, low maintenence heaters are the advantage of gas, expensive and occasionally difficult to acquire gas bottles are the main problem with them. There are many applications where gas is not suitable, if there are any flammables, such as paper, card or fuels then they will be deemed too dangerous. If there are people working in the area then the fumes have to be taken into account and you have to make sure the area is well ventilated. It's also worth remembering that the moisture given off will make any area very humid - so they are not good for drying.
With Diesel the advantage is fuel is cheap and you can always buy road diesel in an emergency if Kerosene or Heating oil are not available. The other advantage is that there are indirect versions available which can either duct warm, dry, clean air in or can be fitted with a chimney to flue the fumes and moisture out.
The disadvantage of diesel heaters is that they need regular servicing and can cost a lot to purchase. There are some heaters which are tricky to get parts for.
Lastly - there are infra-red heaters. These are perfect if you want to warm up one thing or one person in a large open area. Fan heaters won't work well in an open area if it is too big for the heaters - this is no problem for infra red.
What I'm asking you do to do is to look at all the options, consider the drawbacks and the advantages and to make an informed choice. Every heater has a right application, and every application has a right heater - to make sure you buy the right heater for your application - you need to approach it with some knowledge and some thought.
Some applications require a very specific heater.
The right method is:-
1. Work out the volume of the area being heated in cubic metres.
2. Choose a 'K' or insluation value for the area - 1 = well insulated house, 4 = poorly insulated marquee or building site.
3. Make a choice as to the temperature rise you are looking to achieve in degrees C. So if you wanted it at 25 degrees, and you thought the coldest ambient temperature you expect to work from was 5 degrees C, you would have to use 20 degrees as the temperature rise figure.
4. Calculate the heating power needed from the information you have gathered using this equation:- (Volume in Cubic Metres) x Temp Rise in C x 4 x Insulation Value (K) = BTU/Hr needed.
5. If you need the output in kW divide the answer by 3412.
When you have the heat energy needed, you have a start, but you still need to choose the right type of heater for the job in hand. There are many factors to consider.
Firstly, if the power required is less than 10,000 BTU or 3kW then a 3kW Electric Fan heater is easily the most sensible choice. The problem you have is if the needed heat is much more than this - adding multiple heaters can take too much power.
You probably only have a 60A ring main at the most, so if you need 5 x 3kW heaters at 13A each, you will be tripping breakers and blowing fuses - pulling 65A!
When the supply is 110v rather than 230v you need a 32A socket per heater. These pull over 20A for every heater.
When you are using a 230v supply, you are limited to 13A per domestic UK plug socket. This equates to 3kW, more and the fuse will blow every time.
The next option is for 3 Phase Electric Fan Heaters. If you need a 9kW heater then a 16A 3 Phase socket can deliver the required heat. If you need up to 22kW you will need a 32A socket. Over 22kW requires a 63A, 3 Phase Socket.
If you don't have three phase electrics, then you really need to consider burning a fuel. The options are really gas or oil. There are various subdivisions in between these, propane, butane, diesel, kerosene - but we'll treat them as two seperate choices.
Cheap to buy, low maintenence heaters are the advantage of gas, expensive and occasionally difficult to acquire gas bottles are the main problem with them. There are many applications where gas is not suitable, if there are any flammables, such as paper, card or fuels then they will be deemed too dangerous. If there are people working in the area then the fumes have to be taken into account and you have to make sure the area is well ventilated. It's also worth remembering that the moisture given off will make any area very humid - so they are not good for drying.
With Diesel the advantage is fuel is cheap and you can always buy road diesel in an emergency if Kerosene or Heating oil are not available. The other advantage is that there are indirect versions available which can either duct warm, dry, clean air in or can be fitted with a chimney to flue the fumes and moisture out.
The disadvantage of diesel heaters is that they need regular servicing and can cost a lot to purchase. There are some heaters which are tricky to get parts for.
Lastly - there are infra-red heaters. These are perfect if you want to warm up one thing or one person in a large open area. Fan heaters won't work well in an open area if it is too big for the heaters - this is no problem for infra red.
What I'm asking you do to do is to look at all the options, consider the drawbacks and the advantages and to make an informed choice. Every heater has a right application, and every application has a right heater - to make sure you buy the right heater for your application - you need to approach it with some knowledge and some thought.
About the Author:
If you are thinking of buying a portable heating unit, why not you check out the which heater blog for more information and details on choosing the best model. For the best heater calculator on the internet see this link.
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