Heat Recovery Ventilation

Katherine1 · 15-06-2014 10:13am #1

We are building a new home in the south east. Has anyone installed a heat recovery ventilation system and, if so, please advise on how it is working for you, pros and cons etc. Thanks

ShiverinEskimo · 15-06-2014 12:20pm

Best thing I put in. Clean, dry air, no draughts, house keeps the heat and costs feck all to run. Clothes dry indoors very quickly too on rainy days.

Cons are yet to be seen. Cost of filters maybe. Buy a couple of spare packs from your supplier before they finish up.

Worth noting the HRV is only as good as your house's air-tightness allows it to be. Don't bother with a HRV unless you're going to design and build the house to suit it. We also got the same crowd who installed the HRV to install a centralised vaccuum cleaner for feck all more (500 quid odd) as a bundle.

The central vac is the second best thing I put in my house and earned it's place the first week we moved in and hoovered up a ton of dust.

Wally Runs · 15-06-2014 12:43pm

Yes , pretty much as ShiverinEskimo says. Installed properly, you do not notice it. Home fresh and dry, nasty smells removed quickly and easy to use. Airtight home essential.

Katherine1 · 15-06-2014 10:19pm

Thanks for the replies....If anyone could recommend a supplier I would really appreciate a pm. How does it work if windows / doors are open a lot?

sydthebeat · 15-06-2014 10:28pm

Katherine1 wrote: »

Thanks for the replies....If anyone could recommend a supplier I would really appreciate a pm. How does it work if windows / doors are open a lot?

id suggest you do a lot of in-depth research into MHRV systems.

They require an understanding which can be at odds with out "irish" upbringings ie that houses are draughty, that windows have to be left open during the day to 'air the house out' etc

you do not have a need to "open windows a lot" with a HRV system.

Top Corner · 28-09-2014 8:37pm

unless your building your house to passive hauss standards a heat recovery system is pointless as the are only 75 to 85 % efficient in a passive build. if its a regular build your talking 50% efficient at best. there s plenty of new passive hauss certified builders and tradesmen in ireland currently

MizMix · 28-09-2014 10:55pm

Top Corner wrote: »

unless your building your house to passive hauss standards a heat recovery system is pointless as the are only 75 to 85 % efficient in a passive build. if its a regular build your talking 50% efficient at best. there s plenty of new passive hauss certified builders and tradesmen in ireland currently

My understanding is they work well in anything under 3 m3? Ie less air tight than passive but more than the regs

893bet · 28-09-2014 11:47pm

Pretty much impossible to meet current regs with one I am being lead to understand (still looking for a supplier and installer so PMs welcome.)

sydthebeat · 29-09-2014 7:41am

893bet wrote: »

Pretty much impossible to meet current regs with one I am being lead to understand (still looking for a supplier and installer so PMs welcome.)

Without

Its possible but difficult

BarneyMc · 29-09-2014 9:05am

ShiverinEskimo wrote: »

We also got the same crowd who installed the HRV to install a centralised vaccuum cleaner for feck all more (500 quid odd) as a bundle.

That seems like amazing value! Can you please PM me the name of your supplier please? Thanks.

Borzoi · 30-09-2014 9:47am

Top Corner wrote: »

unless your building your house to passive hauss standards a heat recovery system is pointless as the are only 75 to 85 % efficient in a passive build. if its a regular build your talking 50% efficient at best.

Not true. MHVR effectiveness will depend on the air tightness, whether its a PH or not is irrelevant. If installed in a building with poor air tightness the MHVR becomes pointless as infiltration load inceases.

Very happy user of MHVR system, but still a battle (after 4 years) with Mrs B to keep windows shut.

893bet · 30-09-2014 10:10am

Borzoi wrote: »

Very happy user of MHVR system, but still a battle (after 4 years) with Mrs B to keep windows shut.

This is my big fear aswell.

Wally Runs · 30-09-2014 10:55am

It really depends why the windows are opened. Sure with the windows closed the HRV system works as it was designed to and at the it best efficiency as the air flow in the home is through the system.

However, in the late spring, summer and early autumn we have the windows open now and again. Not only are kids in and out, but we need to let heat out of the house (we have a lot of solar gain), so rarely do we need to heat recovery element. We do not have a summer by-pass. During the colder months and night the windows are closed and the system works a treat. At night regardless of the weather we have the windows closed to eliminate traffic noise.

Now if you are having the windows open during that day to cool the house and the heat on in the evening that is another matter.

kennyb3 · 30-09-2014 3:33pm

So you can't switch the system off in summer?

What is the annual running cost btw?

sydthebeat · 30-09-2014 4:09pm

kennyb3 wrote: »

So you can't switch the system off in summer?

What is the annual running cost btw?

no

a 'summer by pass' means the extracted air doesnt have its heat recovered in warm summer days. in this way the system can act like an air conditioning system by inputting cooler fresh air (although not chemically cooled)

the system can be turned off at any time, ive yet to see one which cant.

jiminho · 30-09-2014 7:08pm

Couple of quick questions:

1) Can zonal heating/cooling be accomplished with a MHRV system? Say I wanted the bedrooms to be cooler than the living room - how can that be accomplished? Solar gain differences...
2) In the summer time I would have the big double doors open at the weekend because kids and dogs would be running in an out. Could I have circuit that switches the ventilation off within that room when the doors are open? Is MHRV an all on or all off system - could I have bedroom vents shut, living room vents open at the same time?

For the above to work i would probably need to have airtight rooms and self closing doors

How much kwh does the MHRV use in your home?

Thanks

MicktheMan · 30-09-2014 8:19pm

kennyb3 wrote: »

So you can't switch the system off in summer?

What is the annual running cost btw?

jiminho wrote: »

Couple of quick questions:

2) In the summer time I would have the big double doors open at the weekend because kids and dogs would be running in an out. Could I have circuit that switches the ventilation off within that room when the doors are open? Is MHRV an all on or all off system - could I have bedroom vents shut, living room vents open at the same time?

For the above to work i would probably need to have airtight rooms and self closing doors

How much kwh does the MHRV use in your home?

Thanks

We switch our mvhr off and use our windows during the summer as during this time of the year ventilation isn't required (in the sense of removal of moisture). Other people do not switch their system off / open their windows but use the summer bypass instead (from a security point of view. Thankfully, this isn't an issue for us.)

Electricity running costs are negligible.

Top Corner · 30-09-2014 8:32pm

Borzoi wrote: »

Not true. MHVR effectiveness will depend on the air tightness, whether its a PH or not is irrelevant. If installed in a building with poor air tightness the MHVR becomes pointless as infiltration load inceases.

Very happy user of MHVR system, but still a battle (after 4 years) with Mrs B to keep windows shut.

So you have disagreed and agreed with me

Borzoi · 01-10-2014 3:56pm

Top Corner wrote: »

So you have disagreed and agreed with me

Possibly ;-)

Darbre18 · 06-10-2014 10:12pm

We always have windows and doors opened during summer months,it just gets to hot with all the solar gain.
At first I was manually switching our mvhr system off in the moring then on in the nights to use summer by pass to keep rooms cool.
Last month I set it up to come on when the alarm is armed by using a output on the alarm panel,so during summer months it comes on while setting the alarm going to bed and if we are out during the day.

DeeJunFan · 07-10-2014 10:34am

Top Corner wrote: »

So you have disagreed and agreed with me

Possibly the disagreement is with the terms used.

The unit efficiency will always be what it is depending on the fan speed etc. Not really dependant being in a passive or non house.

The air-tightness of the house will dictate the units effectiveness.

Belle2014 · 13-10-2014 3:28pm

has anyone got a VIking ductless /fliterless HRV system installed?

Heat Recovery Ventilation

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