Can you share your experience if you have used any Heat Recovery Ventilation Sys.?

[floatingisland]

Dear friends,

At the moment, I’m looking for the right ventilation system for my 2 rental properties. One of properties was constructed with weatherboard material, another brick material. Both of them were built in 1970s. Although the different salesmen recommended me of their positive ventilation systems, I still thought it’ll be better if have Heat Recovery or Reclaim ventilation system which have heater built-in, especially it can transfer fresh outdoor fresh air inside rooms, moreover, the fresh air can be heated. The reason why I wanted to have this idea is that, if spend money on any system without effect, it’s wasting money. But, I don’t know whether Heat Recovery System is really worthy to spend extra bucks on that.

If you are using now, or have used any Heat Recovery or Reclaim Ventilation system, could you please share me of your experience, either positive or negative? Also, it’ll very useful for me if you can share the brand of your products.

Thank you very much in advance!

Floatingisland

[sparxNZ]

put in a heat pump and be done with it. one that dehumidifies.
all ceiling penetrations, including heat transfer/recovery systems, downlights, extractor fans etc just let the heat out and cost a fortune in energy over time.

[donnyboy]

how does a heat pump solve condensation in the bedrooms if its installed in the lounge?
I thought heat pumps would have to be primarily on cooling to remove moisture, a rather backward step imo to remove the moisture.

[DazRaz]

put in a heat pump and be done with it. one that dehumidifies.
all ceiling penetrations, including heat transfer/recovery systems, downlights, extractor fans etc just let the heat out and cost a fortune in energy over time.

Heat pumps only dehumidify when in a cooling mode. Not what most people need in winter.

[sparxNZ]

how does a heat pump solve condensation in the bedrooms if its installed in the lounge?
I thought heat pumps would have to be primarily on cooling to remove moisture, a rather backward step imo to remove the moisture.

most have a dehumidifier function. they won't heat while set to dehumidify but they won't cool the room much either. flash ones can be programmed to heat and dehumidify when the air reaches a set humidity point and some will do it automatically via a PID algorithm to try and prevent condensation on cold surfaces like windows etc by calculating the dew point.
I have one big one in the living area in my place and none in the bedrooms, we don't have damp issues because of the way we designed and oriented the house in the first place but if I did I would run it on dehumidify on low fan speed during the day and on heat at night.
purely based on my observations of the domestic installations I've seen over time I reckon the most effective and efficient way to keep a home warm and dry over time is with heat pumps (unless you're designing from scratch). extractors and heat transfer systems only serve to remove valuable heat from a building 24/7 whether they are turned on or turned off. Eventually they will suck out more dollars than a heat pump would have cost you.

[floatingisland]

put in a heat pump and be done with it. one that dehumidifies.
all ceiling penetrations, including heat transfer/recovery systems, downlights, extractor fans etc just let the heat out and cost a fortune in energy over time.

Yes, I installed Heat Pump for one of the property in living area but there are still mould and condenstate problems in 3 bedrooms. The reason why I haven't selected positive ventilation system is that I do have the same concerns that let heat out and cost a fortune. So, I would like to hear some feedbacks from the users of Heater Recovery or Reclaim Ventilation systems. Anyway, thanks for your advice!

[donnyboy]

most have a dehumidifier function. they won't heat while set to dehumidify but they won't cool the room much either. flash ones can be programmed to heat and dehumidify when the air reaches a set humidity point and some will do it automatically via a PID algorithm to try and prevent condensation on cold surfaces like windows etc by calculating the dew point.
I have one big one in the living area in my place and none in the bedrooms, we don't have damp issues because of the way we designed and oriented the house in the first place but if I did I would run it on dehumidify on low fan speed during the day and on heat at night.
purely based on my observations of the domestic installations I've seen over time I reckon the most effective and efficient way to keep a home warm and dry over time is with heat pumps (unless you're designing from scratch). extractors and heat transfer systems only serve to remove valuable heat from a building 24/7 whether they are turned on or turned off. Eventually they will suck out more dollars than a heat pump would have cost you.

which flash heat pumps have the PID algorithm thingy? sounds interesting to have a large heat pump to dehumidify the whole house with it

[sparxNZ]

which flash heat pumps have the PID algorithm thingy? sounds interesting to have a large heat pump to dehumidify the whole house with it

The top of the range *******s are programmable and have PID control of the reverse cycle function. you get a wall mounted thermostat with them. they calculate the dew point from an RTD in the outdoor unit so they know how cold the inside surface of a window is likely to be and keep the indoor temperature and humidity at a level that won't form condensate on windows. not much of it anyway.
they achieve dehumidification and heating at the same time by alternating the reverse cycle, so they might do 5 condensing cycles and then 1 or 2 evaporating cycles to hold the humidity level down. the PID side of things just stands for Proportional Integral Derivative and it's just a way of using a microprocessor to estimate how long and how frequently to run the reverse cycle based on I and D values (not much P one would assume, since it's mostly a discrete final control element.)

Any large heat pump can achieve similar results at far lower cost than a super fancy bell-and-whistles mitsi as long as it has a 24 hour programmable timer. set it to dehumidify on low fan speed for 4-5 hours a day and then switch to heating at night.

Obviously one large heat pump isn't a magic bullet for every dampness problem. An arrangement like this will draw moisture out of the air, carpets, furniture, curtains etc in almost all single level applications provided there aren't too many air leaks around the place but in a two level home it won't work as well.

The HRV, DVS, Moisture Master and other no-name knock off systems have their place I suppose, I've put a few in since the late 90s when they started to make an appearance in a big way and I think the simple through-wall ones are ok. the ones that pull air out of the ceiling and pump it into the house are effective but horribly inefficient and the top of the line moisture master one which has a heat exchanger in it is awesome but costs so much it's prohibitive for all but the cost-is-no-object installations (and you still have to install a heating appliance with it)
A 4 room moisture master plus a heat pump to provide the heat to run everything would cost you probably over $6K fully installed and still isn't as good as 4 individual small heat pumps which would cost about the same, maybe a few hundred more.
The heat transfer systems that just suck air out of the living area and blow it into the bedrooms via one fan and couple of air splits are actually really good if you've got a solid fuel burner and you have loads of free heat, they just get everything so hot the dew point doesn't matter.

EDIT: it would appear that where I wrote the name of the heat pump manufacturer up there the forum crossed it out for me. what's the world come to. it starts with mits, has a u in the middle and ends in bishi.

[WestonSF]

I'm yet to figure the best formula for heating and ventilation yet. In my 3 bedroom house I have a heat pump in the lounge and a positive pressure ventilation system running in the lounge and the bedrooms all the time. I do find it's a little bit colder in the rooms in winter, but don't have crying windows any more or much mould I've noticed...it also just feels more healthy with the ventilation system in. I'm sorta thinking a heat recovery/balanced pressure ventilation system may have been better, but it would have been more expensive. So could be more cost effective to put wall heaters or small heat pumps in each of the rooms.

[Macnz]

Dear friends,

At the moment, I’m looking for the right ventilation system for my 2 rental properties. One of properties was constructed with weatherboard material, another brick material. Both of them were built in 1970s. Although the different salesmen recommended me of their positive ventilation systems, I still thought it’ll be better if have Heat Recovery or Reclaim ventilation system which have heater built-in, especially it can transfer fresh outdoor fresh air inside rooms, moreover, the fresh air can be heated. The reason why I wanted to have this idea is that, if spend money on any system without effect, it’s wasting money. But, I don’t know whether Heat Recovery System is really worthy to spend extra bucks on that.

If you are using now, or have used any Heat Recovery or Reclaim Ventilation system, could you please share me of your experience, either positive or negative? Also, it’ll very useful for me if you can share the brand of your products.

Thank you very much in advance!

Floatingisland

Hi Floatingisland,

We had a very similar dilemma, we looked at a true HRV (Not the mongrel company) The main point around a heat recovery system is that you need (ideally) heat to recover.

They originated from extremely cold climates - (ie Minus 20 degrees outside) with long winters (ie Alaska / Canada) and the houses have double if not triple glazing and usually have a heat source, like a furnace going for 6-9 months of the year centrally heating your home. For this scenario they are perfect.

We opted for positive pressure and it has certainly meet our requirements. I asked for feed back here and on some other forums plus did some hands on research.

I wrote a full review of what I found and the end results. See link below.

http://www.propertytalk.com/forum/showthread.php?38045-Honest-reviews-Ventilation-systems-Part-II

Hope this helps

Cheers
Mac