Whole house heat recovery

[highleigh]

Has anyone any experience of fitting a whole house heat recovery system as a DIY project?

During a complete renovation it makes slot of sense to me to fit ducting to all the rooms while I am building new stud walls upstairs. House is old solid brick detatched so I understand that while the house is not as airtight as modern houses there is still a benefit in doing it, mainly:

I will be able to remove the air bricks which let in slot of drafts and noise.
I have insulated under the ground floor, loft, ceiling and have new dg windows I may fit outside insulation one day.
It just looks such an obvious thing to do - exchange heat from damp warm air to heat fresh air.

House is approx 120sqm, 3 beds, 2 baths. I would be grateful to hear of any others experiences of this sort of system?

Obviious questions to start are which model is best and what size ducting. 205x60 looks like it should fit well in a stud wall.

 

[DeltaT2]

Unless you can get your home very, very airtight mate I'd not recommend it. Of course there's cheap ways of doing it & limit the size of the system. Why not speak to a Ventilation Wholesaler, most do design work also & it would be miles cheaper than any HR Vent company with a flash web site.
HTH

 

[mickyg]

Unless you can get your home very, very airtight mate I'd not recommend it

why not ? I think its a great idea. Its any wonder more people are not investing in heat recovery systems. They improve the air quality in your home, can eliminate damp problems, and its all very simple stuff.

 

[DeltaT2]

Micky many older homes have huge air infiltration problems. But the OP can make his own mind up regarding 'return on cost', any systems we have done have been in new properties & designed by Vent Wholesalers. The systems work well, but I'm not sure how quickly it'll pay for itself??

Even done one with insulated spiral duct running everywhere, huge house it was!!

 

[Agile]

Most of the units that I have seen have a very small heat exchanger and I doubt they are very efficient.

I also wonder what return that would give on the capital cost.

Tony

 

[highleigh]

Thanks for the comments, I dont really expect it to pay for itself but think if I do it DIY from a wholesaler I can install it comparatively cheaply. My logic is that having a centralised ventilation system will make the house more comfortable. I am renovating the whole house and while I dont expect it to be near modern standards I am trying to make the house as air tights possible.

I have seen units for about £800 so assuming I can get ducting for similar this should be a lot cheaper than a fully designed system and will ensure I keep the house well ventilated and should prevent damp and condensation.

Anyone know if this is realistic? Interested if anyone anyspecificexperiencewith any particular model. There does seem to be a fair bit of choice.

 

[mickyg]

i wouldnt recommend it on the basis of saving money, more quality of air in the home. I think they're great in any home, as long as people are not making false promises on what they can do.

 

[Agile]

As I have said above I am not impressed by those I have seen at shows.

Over priced and under specced heat exchangers!

 

[Norcon]

Don't they dump a lot of heat outside?
Heard of a new build property that couldn't be heated that had one of these things installed and someone just turned it off and no problems since.

 

[mickyg]

As I have said above I am not impressed by those I have seen at shows.

Over priced and under specced heat exchangers!

]

Well I doubt you'll get much idea how effective they are at a show tony

 

[mickyg]

Don't they dump a lot of heat outside?
Heard of a new build property that couldn't be heated that had one of these things installed and someone just turned it off and no problems since.

around 10-12% heat is wasted to outside, but it should balance out with air movement and reduced damp/moisture. I cant see how a 10% loss would prevent a house heating unless if was exactly 10% undersized
Maybe it wasnt working properly or it was on summer setting

 

[dcawkwell]

Like most ECO stuff.
Not worth the cost.
Better to put your money into solar panels or solar hot water.
Or just keep it in the bank.

 

[DeltaT2]

Thanks for the comments, I dont really expect it to pay for itself but think if I do it DIY from a wholesaler I can install it comparatively cheaply. My logic is that having a centralised ventilation system will make the house more comfortable. I am renovating the whole house and while I dont expect it to be near modern standards I am trying to make the house as air tights possible.

I have seen units for about £800 so assuming I can get ducting for similar this should be a lot cheaper than a fully designed system and will ensure I keep the house well ventilated and should prevent damp and condensation.

Anyone know if this is realistic? Interested if anyone anyspecificexperiencewith any particular model. There does seem to be a fair bit of choice.

With a £1.6K budget mate, you should get a farly good system, but speak to a Vent Wholesaler.

 

[Onetap]

i wouldnt recommend it on the basis of saving money, more quality of air in the home. I think they're great in any home, as long as people are not making false promises on what they can do.

There was a study of cost saving & energy efficiency measures carried out (by Which, I think) 25 or so years back. A ventilation system was one of the most effective measures IF the cost savings of cleaning were considered.

If the building is kept at a positive pressure with filtered air, it reduces the infiltration of outside air and airborne dust. To achieve this you'd need a pressure sensor and a speed control of the fan, to maintain the pressure gradient as filters became dirty and more resisant to the air flow. It is standard procedure with clean rooms and containment laboratories (but with a negative pressure regime). Having said that, the controls for such a systems would be very expensive and most of the domestic systems I've seen were built to a very limited budget.

 

[Agile]

I have some on 28 kW gas dryers. They have an area of about 4 sq m of aluminium heat exchanger and work with a temp diff of about 40 C.

The ones I have seen have an area of about 0.5 sq m and a plastic exchanger. Since they work on a diff of about 10 C then I dont see much heat getting transferred.

Does anyone have any figures of temps achieved on the domestic units?

Tony