# Workshop Heating



## Blackswanwood (14 Apr 2019)

I am having some plans drawn up for a workshop. It is going to be brick/block construction with a floor area of circa 30 sqm. The workshop will be detached from the house so needs independent heating.

The architect is suggesting using an air to air heat source pump. I am a bit sceptical but can only find positive “advertorials” online for them. If they are so good why are they not more common?

Any thoughts or advice will be most welcome.


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## Steve Maskery (14 Apr 2019)

I don't know much about them, but I wish I'd put something like that in my workshop, It could have been a ground source one either, as we were digging up a lot of the garden anyway.
PM MikeG. I think he is an expert on this sort of stuff.
S


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## TFrench (14 Apr 2019)

Main thought is to insulate as well as possible. Also, you don't need to heat it like a house - just maintain a constant temperature to keep from getting condensation on tools.


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## Rorschach (15 Apr 2019)

They are the norm in new builds now.


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## Blackswanwood (15 Apr 2019)

Rorschach":34bd0asr said:


> They are the norm in new builds now.


Not quite I believe. They are normally still warm radiators or under floor heating. What he is proposing blows warm air https://www.greenmatch.co.uk/blog/2015/ ... -heat-pump. Thanks.


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## Doug B (15 Apr 2019)

How is your house heated, my detached workshop simply has 3 rads off the combi boiler in the house, installed when I built the workshop the cost was very small.


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## Rorschach (15 Apr 2019)

Blackswanwood":mi2cmgpo said:


> Rorschach":mi2cmgpo said:
> 
> 
> > They are the norm in new builds now.
> ...



My apologies, I misread, it is air source heat pumps feeding a hot water system that are the norm where there is no mains gas, and the proposal is to stop new houses connecting to the gas within a few years.
The new estate where my SIL lives is all air source as it's rural. There is no gas and they were not allowed to install oil fueled boiler which is what the older houses in the area all use.


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## MikeG. (15 Apr 2019)

Blackswanwood":6tcduuat said:


> I am having some plans drawn up for a workshop. It is going to be brick/block construction with a floor area of circa 30 sqm. The workshop will be detached from the house so needs independent heating.
> 
> The architect is suggesting using an air to air heat source pump. I am a bit sceptical but can only find positive “advertorials” online for them. If they are so good why are they not more common?
> 
> Any thoughts or advice will be most welcome.



An air source heat pump for 30 sq metres? Hmmmm...... 

Air source heat pumps have been the subject of one of the most successful rebranding and marketing exercises in recent history. They're an airconditioning unit, that's all. They're just fitted the other way around, with cold air exhausted to the outside rather than the inside of a building. They never achieve the results that are quoted for them, and it is really just glorified electric heating, which in Britain means it isn't doing very much for your carbon footprint if that's a concern.

Personally, I think it a mistake to make a workshop out of brick and block, because of the thermal inefficiences of the wall compared with a timber framed wall as relates to an intermittently heated space. You'll get a warmer, more responsive, and cheaper to run workshop if you build with timber instead.

Finally, using an airconditioner for heating a workshop means a fan blowing air around, and that isn't necessarily a good thing in a dusty environment.


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## Blackswanwood (15 Apr 2019)

Doug B":2usmiizp said:


> How is your house heated, my detached workshop simply has 3 rads off the combi boiler in the house, installed when I built the workshop the cost was very small.


We are on biomass (wood pellet). If the workshop were closer to the house that would have worked but it is circa 20 metres away.


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## MikeG. (15 Apr 2019)

Blackswanwood":2bq9ol84 said:


> .....We are on biomass (wood pellet)........



You could install a wood pellet stove. They burn the same fuel, but are a stand-alone unit acting just like a woodburner. Or you could install a woodburner.


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## Blackswanwood (15 Apr 2019)

MikeG.":1oj9wkx3 said:


> Blackswanwood":1oj9wkx3 said:
> 
> 
> > I am having some plans drawn up for a workshop. It is going to be brick/block construction with a floor area of circa 30 sqm. The workshop will be detached from the house so needs independent heating.
> ...



Thanks Mike. That pretty much sums up what I suspected!

I was originally going down the timber route but we are in the curtilage of a Grade 1 listed building. What we are doing is reinstating an old outbuilding which in the scheme of other stuff the planners are happy with. We are going for a high spec on insulation which hopefully is a close second best to timber.

As for heating I think I will put an electric radiator in to keep the temperature above the dew point with a small wood burning stove for when it is really cold.


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## MikeG. (15 Apr 2019)

Grade 1!! Bloody hell.....

Nonetheless, replacing the inner blockwork skin with a timber frame full of insulation would make a warmer and more efficient building.


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## Blackswanwood (15 Apr 2019)

MikeG.":qm9h4ma1 said:


> Grade 1!! Bloody hell.....
> 
> Nonetheless, replacing the inner blockwork skin with a timber frame full of insulation would make a warmer and more efficient building.



Yes ... five minutes with the planners and you start wondering whose house is it anyway!

That’s a really good idea ... it should also increase the effective floor space?


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## MikeG. (15 Apr 2019)

Yes, because you only need a 50mm cavity. In fact, as it is under the 30sq floor area rule, and therefore not subject to Building Control (subject to distance from boundaries), you could use a 25mm cavity between the outside of the timber frame and the inner face of the brick. Just make sure you put the sheathing board on the inside of the timber framing, not the outside. Make sure the void is ventilated.


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## Blackswanwood (15 Apr 2019)

Thanks Mike. Builder concurs it’s a good idea. Much appreciated.


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## Peterm1000 (16 Apr 2019)

MikeG.":1319n5a9 said:


> Blackswanwood":1319n5a9 said:
> 
> 
> > I am having some plans drawn up for a workshop. It is going to be brick/block construction with a floor area of circa 30 sqm. The workshop will be detached from the house so needs independent heating.
> ...



Plus the fan noise to annoy your neighbours... Although I guess that would be drowned out by powertools!


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## samhay (16 Apr 2019)

The fan noise from a heat pump is generally pretty minimal, so unlikely to upset the neighbours. They have become the standard heating option in much of the Antipodes, which as Mike said is a beautiful piece of sales rebadging.

As someone who potters in a brick/stone shed, the wooden interior is a good choice.


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## Woody2Shoes (21 Apr 2019)

My sister uses an air source heatpump to heat her pool - it's in a big garden. If it were within a few metres of my garden (i.e. in a typical suburban setup) it would annoy me.
I think that pool pumps/boilers/heaters are something that neighbours fall out over in the Antipodes and elsewhere.
Cheers, W2S


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