replacement for 1970's hot air gas central heating

MrsBrush

We have recently moved into a house with a 1970's gas hot air heating system. It is surprisingly efficient as a heat source, but we are also aware that it is starting to show its age and parts are very difficult to get hold of now. We have just had to patch up the fan to keep it running and it seems that the hot water part of the system isn't working at all and our hot water is coming from an immersion heater. We have a lot to do in the house, and whilst replacing the heating is on our list of priorities we ideally want to wait until next spring / summer before replacing it. it seems that a replacement boiler for the hot air system is not an option because just it isn't how things are done any more!

This brings us to the conundrum.

Because it is a hot air system, we have no radiators anywhere, so we would have to get a full system installed as a gas central heating replacement. Or we go electric... straight air heat pumps seem to be the government's preferred option but not convinced by the hype.

We are liking having the freedom of no radiators in the way (can be unsightly and they restrict where furniture can go), not to mention the disruption of floorboards up everywhere to install everything. This has led us to looking at combined heat / cooling units throughout, all high wall / ceiling mounted, as these were efficient in our extension in the last house. Downside is needing the external units and the potential for needing planning consent, and keeping the water hot with an electric immersion system.

The alternative is a gas central heating system, which in many ways is the 'known' and conventional option. This would free up a huge amount of useable space in our large but terribly laid out kitchen that is almost there for effect rather than having any real and useable working / prep space. The kitchen is another 'known' and planned for project - it is on the 'not yet' list as it is dependent on what we decide to do about the heating, as that will then give us 2 very different layout options - both workable and effective.

It seems that cost-wide there isn't much in this - would probably cost about £6k either way as we are essentially going to be starting from scratch. Likewise, disruption for installation is inevitable either way. 

What is the best way to go? Just looking for practical advice, ideas and future proofing considerations.

silvercar

A friend looked at a house with this heating system. When it comes to replacement, you have to allow for closing up all the air corridors that currently bring heat into the rooms. You can't just seal them off, they need removing/ filling or venting. this is not only to prevent damp but also the space they occupied needs to be able to support whatever weight you want to put on them.

Ectophile

You can still get gas warm air heaters if you hunt around.  My mum had her old one replaced not that long ago.

danrv

I had a similar dilemma a while back with my electric warm air system. 
A thread here on my heating upgrade.
https://forums.moneysavingexpert.com/discussion/6269423/7-8k-for-aircon-system

As you have mains gas, maybe look at getting the warm air system renewed or overhauled.
I wouldn’t go with gas central heating install with the gradual fossil fuel reduction now in place.
ASHP wet system is the usual replacement for gas central heating. Can be expensive though but there’s government funding available.
At least it would be greener, future proof, an investment and properly optimized being a ‘from scratch’ install.
Does depend on planning permission though if this is required. 

MrsBrush

Thank you all. Some good ideas, and it has given me food for thought. Hopefully we can wait till the spring before we need to make the changes.

I hadn't realised you can still get new warm air boilers, looks as though that might be the cheapest and easiest option. Having done a bit of a search, it seems that you can get modern standard Johnson and Starley boilers that are not as expensive as a full system install - the boilers seem to be £2-3k and I would expect a further £1k for install costs (not quoted, just a finger in the air)

As I say, the current system is good (just a bit noisy because of the fan). Cant really comment on efficiency overall, but it does only need to be on for an hour and the whole place is warm and stays warm! The engineer who patched it up said that the Johnson and Starley boiler must be at least 40+ years old. The water heating system no longer seems to work, and we haven't investigated a repair at this stage but the pipes, ducting etc is all there.  The unknown of course is whether the ducting is in good condition? If that needed replacing that would obviously change things.

The gas CH option as a new install is not an attractive prospect, for lots of reasons, but would give us exactly what we need, and we know it will work.
The AC option is a known quantity for us, because we have had experience of this previously (but with no hot water), so we would either need to retain the electric immersion heater or go with a wet ASHP. We would possibly run into problems with PP, as we are semi-detached and we only around 4 meters from our next door not attached property.

I still don't think I understand why the water based system attracts the government grant funding, but the 'dry' system doesnt? Particularly where the wet system seems to be less efficient at heating overall... 

danrv

MrsBrush said:

I still don't think I understand why the water based system attracts the government grant funding, but the 'dry' system doesnt? Particularly where the wet system seems to be less efficient at heating overall... 

I think it’s because dry systems have both cooling and heating. The new grant is supporting heating only (Clean Heat Grant).