Do grants cover warm/blown air heating systems?

Spies

My dads gas warm air system was condemned some years ago now so he uses a wood burning stove to keep warm, are the boiler grants applicable to replace warm air heating with an equivalent?

He does not want central heating because it would be a lot of upheaval putting radiator pipes in.

Thanks

Netexporter

Air-to-air heat pumps are regarded as air-conditioners, so no grants available, AFAIK.

However, A2A units are relatively cheap, so it might be possible to connect one to the existing ducting.

On the other hand, warm air systems are pretty inefficient, one of the reasons the US use twice as much energy, per capita, as Europe, so if it was me, I'd put up with a few days disruption having a wet system installed.

Reed_Richards

But a warm air system ought to be more energy efficient than a wet system.  With warm air you make the air as warm as you want your rooms to be.  With a wet system you have to heat water to 40 to 50 C (typically) to make the rooms 21 C (typically).  The efficiency of an ASHP decrease the greater the difference between the outside air temperature and the temperature you are heating to.  So directly heating air to 21 C is much more energy efficient than heating water to 45 C in order to make the air in the room 21 C.   

Netexporter

Reed_Richards said:

But a warm air system ought to be more energy efficient than a wet system.  With warm air you make the air as warm as you want your rooms to be.  With a wet system you have to heat water to 40 to 50 C (typically) to make the rooms 21 C (typically).  The efficiency of an ASHP decrease the greater the difference between the outside air temperature and the temperature you are heating to.  So directly heating air to 21 C is much more energy efficient than heating water to 45 C in order to make the air in the room 21 C.   

Water has over 4 times the heat carrying capacity of air for a given mass. Water is getting on for 1000 times denser. There's a reason when internal combustion engines ans EV batteries are most successfully cooled with water.

Also 1960s (I'm guess that's the vintage, as that was when warm-air heating was last in vogue) ducting would probably not be adequately insulated, if at all. You might get back some the lost heat, in some cases, but an uninsulated duct in a roof space, for example, would just lose heat to outdoors.

QrizB

Reed_Richards said:

But a warm air system ought to be more energy efficient than a wet system.  With warm air you make the air as warm as you want your rooms to be.  With a wet system you have to heat water to 40 to 50 C (typically) to make the rooms 21 C (typically).  The efficiency of an ASHP decrease the greater the difference between the outside air temperature and the temperature you are heating to.  So directly heating air to 21 C is much more energy efficient than heating water to 45 C in order to make the air in the room 21 C.   

And that's part of why air-to-air heat pumps have a higher SCOP than air-to-water ones do.

Sadly, our government seems to have decided that air-to-air heatpumps are unworthy of the £7.5k grant.

(I once had a house with warm air heating, heated from a huge central storage heater. It was lovely and warm, and didn't seem expensive or inefficient. Sadly the fan failed and it was uneconomic to repair it, so it was replaced by GCH.)

Reed_Richards

Netexporter said:

Water has over 4 times the heat carrying capacity of air for a given mass. Water is getting on for 1000 times denser. There's a reason when internal combustion engines ans EV batteries are most successfully cooled with water.

That may be entirely true but I cannot fathom why it could be relevant.

Netexporter said:

Also 1960s (I'm guess that's the vintage, as that was when warm-air heating was last in vogue) ducting would probably not be adequately insulated, if at all. You might get back some the lost heat, in some cases, but an uninsulated duct in a roof space, for example, would just lose heat to outdoors.

This is relevant.  It's not so good heating the air efficiently if a lot of heat is lost from the ducting in the loft.  Of course if that happens now then it has always been a problem.

Spies

My dads is under floor ducting so it's not so much a problem, so back to the original question. 

Do grants cover replacement of a warm air system? 

ArbitraryRandom

Netexporter said:

Air-to-air heat pumps are regarded as air-conditioners, so no grants available, AFAIK.

QrizB said:

Sadly, our government seems to have decided that air-to-air heatpumps are unworthy of the £7.5k grant.

I think both of these posts answer your question? 

QrizB

Hypothetically, I guess you could fit an air-to-water heat pump, then run the hot water through a water-to-air radiator embedded in the existing warm air system? I'm imagining something like a car radiator, with tubes and fins.

A system like that would probably qualify for the grant.

Bit I've never seen one, and I suspect that you will struggle to find an installer.

Netexporter

QrizB said:

Hypothetically, I guess you could fit an air-to-water heat pump, then run the hot water through a water-to-air radiator embedded in the existing warm air system? I'm imagining something like a car radiator, with tubes and fins.

A system like that would probably qualify for the grant.

Bit I've never seen one, and I suspect that you will struggle to find an installer.

I was thinking along the same lines. I think the real stumbling block is that an grant aided installation would have to use MCS approved kit, and this would be essentially a one-off prototype.

ArbitraryRandom

Can you only get the grant for the installation of a full system?

Or could you have the heat pump purchased and installed using grant funding, then have your own plumber/heating engineer come in to carry out the rest of the work? 

It's actually something I've wondered about before when it comes to properties with undersized (for a heat pump) radiators - if a home owner could have the grant now to install the pump then replace the radiators at a later date as funds allow, or if the conditions of the grant require a full operational set up.