HRV and HEATPUMPS
Jan 21st 2008, 11:23 pm
#1
ex corrections officer
Thread Starter
Joined: Aug 2006
Location: was Bucks.UK now Dunedin. NZ
Posts: 39
HRV and HEATPUMPS
What are the pros and cons of these two systems?
Jan 22nd 2008, 3:22 am
#2
BE Forum Addict
Joined: Feb 2005
Location: Back in NZ & loving it - living in Orewa
Posts: 1,183
Re: HRV and HEATPUMPS
Heat pumps are great - up to 300% heating efficiency, thermostatically controlled etc
I'm a bit of a HRV cynic though, similar sales hype to double glazing in the bad old days. There isn't much heat in your attic on cold days when you need it (try putting a radio thermometer up there if you don't believe me because this is what I did). Sure, they ventilate your house - so does leaving a window open. The price charged for these systems in way in excess of the parts and labour involved in fitting one, hence the advertising budget and shiny cars for the sales people. Just my $0.02 though
I'm a bit of a HRV cynic though, similar sales hype to double glazing in the bad old days. There isn't much heat in your attic on cold days when you need it (try putting a radio thermometer up there if you don't believe me because this is what I did). Sure, they ventilate your house - so does leaving a window open. The price charged for these systems in way in excess of the parts and labour involved in fitting one, hence the advertising budget and shiny cars for the sales people. Just my $0.02 though
Jan 22nd 2008, 6:40 am
#3
Joined: Nov 2006
Posts: 2,225
Re: HRV and HEATPUMPS
Heat pumps will cool in summer and help to reduce the humidity. Downside is that as soon as you open an outside door or a window the heat escapes - no thermal mass to retain the heat.
Jan 22nd 2008, 11:21 pm
#4
Forum Regular
Joined: May 2007
Posts: 38
Re: HRV and HEATPUMPS
Heat recovery should always be treated as an expensive add on as it takes decades to pay for itself and get your inital investment back.
Heat pumps fall into two catagories - Ground source and air source (they can take heat from a mass of water as well).
It does what it says on the tin it takes heat from the ground or the air and dumps it (controlled) into your home in the form of hot water for either domestic (showers etc) or heating (radiators or convectors which can be used in reverse to take the heat from the home and dump it into the air/ground.)
For ground source you need to either lay pipes in coils (slinkys) along a trench or trenches of about 90 mts long. The big downside is that your land is then unable to be built on etc.
OR the best most, efficient option is to drill 2/3 vertical shafts to 50 mts ish (dependant on project size) and drop in a flow and return connected by a U bend then the hole is backfilled with a special grout.
Its mindblowing cause after 3 - 5 years when its paid for itself your heating and hotwater/aircon is 80% (min) cheaper than your neighbour who hasnt got it.
Course it can be linked into a swimming pool as well.
Consider Solar Hot Water as well working alongside the heat pump - fantastic.
Needs to be looked into properly and it is advisable to get someone to project manage as you can easily get it wrong.
Will be over to NZ end of the year and will be working in alternative energy PM me if you have any questions.
Heat pumps fall into two catagories - Ground source and air source (they can take heat from a mass of water as well).
It does what it says on the tin it takes heat from the ground or the air and dumps it (controlled) into your home in the form of hot water for either domestic (showers etc) or heating (radiators or convectors which can be used in reverse to take the heat from the home and dump it into the air/ground.)
For ground source you need to either lay pipes in coils (slinkys) along a trench or trenches of about 90 mts long. The big downside is that your land is then unable to be built on etc.
OR the best most, efficient option is to drill 2/3 vertical shafts to 50 mts ish (dependant on project size) and drop in a flow and return connected by a U bend then the hole is backfilled with a special grout.
Its mindblowing cause after 3 - 5 years when its paid for itself your heating and hotwater/aircon is 80% (min) cheaper than your neighbour who hasnt got it.
Course it can be linked into a swimming pool as well.
Consider Solar Hot Water as well working alongside the heat pump - fantastic.
Needs to be looked into properly and it is advisable to get someone to project manage as you can easily get it wrong.
Will be over to NZ end of the year and will be working in alternative energy PM me if you have any questions.
