heat Recovery System -Payback

jfh

hi all,
we're in the process of building a two storey house, 2200 sq & have been quoted 4900 & 5700 from both ProAir & Beam respectively.

my question is how long does it take for this to pay for itself?
i've never been in a house with HRV, anyone have it in & see benefit/none

any feedback on both systems, greatly appreciated.

delfagio

The benefit to HRV is that it keeps the house supplied constantly with fresh air, but also that it's not cold air coming in, it's heating the air coming in to the temperature inside the house or near enough. Hence the name Heat Recovery.

I have HRV and to be honest, I wouldn't be without it. I never open the windows unless it's too hot inside during summer.

Regarding payback, it would be different for everyone as nobody achieves the same level of airtightness so payback does vary. I don't know how you would really quantify it.

What level of airtightness do you plan to achieve.

Metric Tensor

Honestly - the payback period is probably HUGE. You will probably never save the money in heating bills that it costs.

It is, in my opinion, totally necessary in order to make modern "air-tight" houses comfortable. It's benefit comes from making your house comfortable rather than the money it will save you.

Modern houses without designed ventilation are very stuffy and sometimes quite uncomfortable in my opinion.

sydthebeat

jfh wrote: »

hi all,
we're in the process of building a two storey house, 2200 sq & have been quoted 4900 & 5700 from both ProAir & Beam respectively.

my question is how long does it take for this to pay for itself?
i've never been in a house with HRV, anyone have it in & see benefit/none

any feedback on both systems, greatly appreciated.

from my experience, the extra "upgrades" you need to include to comply with minimum regulations when you choose NOT to install MHRV costs in and around the same as a specification with MHRV....

its not simply a choice of "specification X" with or without MHRV...
its specification X (with MHRV) costs the same as specification Y (without MHRV)

so with that in mind you may as well get the benefit of the MHRV.

The success of the system is depended on the design of the system, the maintenance of the system and the management of the occupants.

Calahonda52

As above:
the design, install, commissioning and maintenance are absolutely critical as is a good Air Tightness [A/T] level.

A system that meets those criteria will result in a house that will be a joy to live in so rather than focus on brands, focus on the above.

What is the target A/T number.
What is the rated efficiency of the MHVR units?
Is there a summer bypass?
does it have the ability to have a cooling coil heated to take the humidity out of the air on days like we have had recently?

Some reading material on the topic
The link is on MHVR only, the attachment is on a wider range of domestic energy related kit

http://www.fourwalls-uk.com/wp-content/uploads/2016/03/MVHR-Meta-Study-Report-March-2016-FINAL-PUBLISHED.pdf

The key errors I have seen are:
pipe layout done much too late in the design, leading to
=>smaller ducts
=> higher flow rates at normal operation fan speeds
=> unacceptable noise levels at night in bedrooms
=> irritated spouses

unit in inaccessible locations for ease of filter replacement.
poor commissioning
penny pinching on quality silencers/ or omission entirely [ Ah sure you don't need them]
keep well

Ps payback: what is it on an expensive kitchen versus el cheapo:D

murphaph

The primary function of mechanical ventilation with or without heat recovery is to improve comfort levels and by extension ensure a healthy climate for the building. Energy savings are a side benefit if any are present. Given that, I don't think mechanical ventilation ever pays off in financial terms because it'll always be cheaper to manually ventilate, but the comfort levels won't be anywhere near as good.

ArnieSilvia

I spend very little for gas heating (70-100 euro bill per month including cooking and hot water) during winter months, maintaining 21 degrees all day and 19 degrees all night. Now I can't bring temps down below 24 degrees since May, but that's because of no summer bypass (I'll make a separate fan system and controllers to sort this joke out). House 100ish sqm, BER A2.
Make sure you have a look at fan size before buying, my unit fans (BEAM mvhr) are smaller than ones installed in cars hence noisy! And apparently this unit is way bigger than recommended?!

As other poster said, good system pays back in comfort of living. Whenever I go to visit someone I always have the same reaction - brrrrrr, cold

To put that into perspective, in a traditional 3 bed house, same level of comfort would cost approx 500-700 euro per month nov-apr plus you would have draughts from wall vents

ontour2

ArnieSilva,
Was your mvhr fitted to a new build or a renovation? What was the approximate cost? Any information is appreciated!

jfh

many thanks for the thorough replies, it is something i know very little about, builder gave the 2 options & going about researching it now.

so i guess it's more about providing more comfortable living than actually saving money, i do get that. Some of the new houses are too warm, there's very little air circulation. my only concern is as sydthebeat pointed out, the management of occupants, am i going to be screaming at wife & kids to close the door constantly?!
is that too simplistic view of it,

also the maintenance, are we just talking about changing filters on a yearly basis?

Metric Tensor

Firstly from my experience there isn't a father in the country who doesn't spend his life shouting at the kids to close the doors!!! ;-)

Opening the doors or windows only has the same effect as it would in any other house. It let's heat escape from the house. So obviously if your door is left open you can't bitch about the HRV unit not recovering enough heat because you're letting the heat escape. This is the same as any house.

So my advice is just treat the house as you normally would. The HRV unit will continue to deliver ventilation just won't be recovering heat as well if you have doors or windows open. In practice you should hopefully find that you don't feel the desire to open the windows as much - but there's no HRV policeman who's going to call to your house to check if your windows are open or closed!

Calahonda52

jfh wrote: »

many thanks for the thorough replies, it is something i know very little about, builder gave the 2 options & going about researching it now.

so i guess it's more about providing more comfortable living than actually saving money, i do get that. Some of the new houses are too warm, there's very little air circulation. my only concern is as sydthebeat pointed out, the management of occupants, am i going to be screaming at wife & kids to close the door constantly?!
is that too simplistic view of it,

also the maintenance, are we just talking about changing filters on a yearly basis?

Glad to give food for thought!

The filter question depends on what grade you go for: e.g. there are very fine filters to take out pollens and other fine airborne stuff that will require changing maybe twice a year.
Normal filters would be annually, assuming the intake is not next to a quad bike dust track.
Equally if you live beside a busy road you might want to ensure diesel particulates are being removed.

I have a mouse pad from these guys
http://www.camfil.ie/Filter-technology/
Its mainly industrial but it will get you started
as will this
http://www.fairair.eu/en/information-about-mvhr-ventilation/?gclid=CO6qpYGJ8M0CFQNQ2wodi2cDOQ

The key is ease of access and use a standard, easily sourced filter than some proprietary one

jfh

Calahonda52 wrote: »

Glad to give food for thought!

The filter question depends on what grade you go for: e.g. there are very fine filters to take out pollens and other fine airborne stuff that will require changing maybe twice a year.
Normal filters would be annually, assuming the intake is not next to a quad bike dust track.
Equally if you live beside a busy road you might want to ensure diesel particulates are being removed.

I have a mouse pad from these guys
http://www.camfil.ie/Filter-technology/
Its mainly industrial but it will get you started
as will this
http://www.fairair.eu/en/information-about-mvhr-ventilation/?gclid=CO6qpYGJ8M0CFQNQ2wodi2cDOQ

The key is ease of access and use a standard, easily sourced filter than some proprietary one

Calahonda52 appreciate the reply, none of us suffer from allergies & it will be built out in the country so no worries regarding the diesel particles!
i'm still trying to get through your 2 previous link, a bit heavy for a newbie:)

jfh

Metric Tensor wrote: »

Firstly from my experience there isn't a father in the country who doesn't spend his life shouting at the kids to close the doors!!! ;-)

Opening the doors or windows only has the same effect as it would in any other house. It let's heat escape from the house. So obviously if your door is left open you can't bitch about the HRV unit not recovering enough heat because you're letting the heat escape. This is the same as any house.

So my advice is just treat the house as you normally would. The HRV unit will continue to deliver ventilation just won't be recovering heat as well if you have doors or windows open. In practice you should hopefully find that you don't feel the desire to open the windows as much - but there's no HRV policeman who's going to call to your house to check if your windows are open or closed!

think i had already my mind made up, but you have confirmed it.

ArnieSilvia

ontour2 wrote:

ArnieSilva, Was your mvhr fitted to a new build or a renovation? What was the approximate cost? Any information is appreciated!

It was a new build completed in 2013. I'll confirm mvhr unit details over weekend