Home Ventilation - Separating the Salient from the Sales

Forums › Home Workshop DIY › Home Ventilation - Separating the Salient from the Sales - Your thoughts?

1 | 2 | 3 | 4 | 5 | 6

20520 posts

Uber Geek
+1 received by user: 4798

#827266 28-May-2013 19:38

TinyTim:
mattwnz: I think cars produce more toxic fumes than woodburners,

Hmm...

From Victoria University: Wood burning fires a winter health hazard

"Travis didn’t expect his research results to show that, particularly in Auckland, wood burning fires contributed more particle pollution than vehicle emissions in the winter months.

'That was a surprise, especially because most people think road transport is the leading cause of air pollution.' "

They did say it was a surprise. However that would include all types of wood burners and open fires too. The new ones, and pellet fires, are far more efficient than fires sold even 10 years ago, and these newer ones would be in the minority.

Batman

Mad Scientist
30014 posts

Uber Geek
+1 received by user: 6217

Trusted

Lifetime subscriber

#827316 28-May-2013 20:46

timmmay:
joker97: 1) are there any other alternative ventilation systems that is cheaper than DVS?

2) ... in Dunedin?

3) any ventilation systems that recycles and reconditions rather than PPV? (would it be better?)

You could dehumidify and warm, but that won't bring new oxygen in.

DVS is probably one of the most expensive. Just search for options, like Cleanaire I suggested.

mattwnz: The newer ones are a lot better. Plus if you get one that is installed in the wall, rather than a freestanding one, the flue can be put on the outside of the insulation. I think cars produce more toxic fumes than woodburners, it is all about managing the risk, otherwise most things would be banned, life has many dangerous and toxic things in it.

I live near a motorway and I walk a lot. One wood burner seems to make it a lot more difficult to breathe than all the cars on the motorway.

timmmay was your kit bought separate and you got a sparky to install it? someone pointed me to one of those kits in another thread but for the life of me I've been searching the entire day and cannot find that thread *sigh

timmmay

20859 posts

Uber Geek
+1 received by user: 5350

Trusted

Lifetime subscriber

#827325 28-May-2013 20:52

What kits do you mean? My DVS was put in before I bought the house, as was the fireplace. The place I live for ventilation systems is these guys.

evileric

9 posts

Wannabe Geek
+1 received by user: 4

#827345 28-May-2013 21:18

Hi there
Been a long-time lurker of Geekzone forums, so thought it was about time to give something back

About 8 years ago we renovated our 1940’s Wellington home with single and double glazed aluminium windows & french doors (should have gone 100% double-glazed but that’s another story), full insulation (walls, ceiling, under-floor) and heatpump in the lounge. We have bathroom, laundry and kitchen extractor fans that we always use.

The house is warm and comfortable (good solar gain) but we suffered years of terrible condensation on the windows and doors for many months of the year – even on the double glazed !! We used to leave windows open to air the house etc but it didn’t seem to help.

I did a heap of research on how to solve the condensation issue and decided on heat recovery ventilation, as I wasn’t convinced with PPV for the reasons already mentioned.

My choice came down to the Moisturemaster HX and the Smartvent Synergy. I ended up choosing the former as I perceived it to have better quality fans and exchanger. It also has a built in heater that will fire up if the temperature drops below a designated amount but I haven’t really used this feature to be honest.

I bought the system through a ventilation supplier directly, not the MoistureMaster agent, and installed it myself saving quite a bit of $$$$. Again I did a heap of research on installing the ducts correctly to get the optimal airflow etc and the supplier was really helpful. It was a bit daunting at first but actually pretty straightforward if you’re a little bit handy and not too scared about cutting holes in your house!!

So I finished the installation towards the end of last winter and I can honestly say that the condensation went away overnight – even on the aluminium frames. This was WAY beyond my wildest expectations and we wish we’d done it years ago now!!

I’ve kept the system running all year long, but in summer I just had the outside air coming in only (turned off the extract fan) as I didn’t want to heat it with the inside air as we were trying to keep cool!! You can buy a summer bypass system with a damper but this cost quite a bit more from memory.

You are supposed to change the filters yearly but I noticed a drop in performance recently so I changed them last weekend. I was shocked how dirty and clogged they were so I might have to change them more regularly. Straight away performance lifted again.

To give you an idea I just checked the control panel (the system comes with air temp sensors) and the air in the lounge is being expelled at 20c (heatpump heated). The outside air being drawn in is 4c, but being warmed up to 17c and fed into the bedrooms. Obviously the warmer it is outside the better the recovery temperature. There is usually a 1-2c difference.

So to sum up I am super happy with this system and so glad we installed it after taking what I thought at the time was a bit of a punt! Yes, heat exchange systems are more expensive than the PPV systems but they make much more sense!

Stan

929 posts

Ultimate Geek
+1 received by user: 183
Inactive user

#827346 28-May-2013 21:18

TinyTim:
mattwnz: I think cars produce more toxic fumes than woodburners,

Hmm...

From Victoria University: Wood burning fires a winter health hazard

"Travis didn’t expect his research results to show that, particularly in Auckland, wood burning fires contributed more particle pollution than vehicle emissions in the winter months.

'That was a surprise, especially because most people think road transport is the leading cause of air pollution.' "

It depends what people burn in them. If you are burning wet or treated timber and whatever other rubbish people put in there fires then yes they put a large amount of crap into the air.

However burning dry wood on a modern fires with particle emission of sub .7 grams per kilogram of dry wood burnt are actually rather environmentally friendly. Besides no heat pump can beat the shear heat or longevity that you will get off a modern fireplace, some fires exceed 25 kw output. Fireplaces heat your whole house (esp with a heat transfer kit) high wall heat pumps don't there is definitely still a place for fireplaces.

Back on topic to be honest go on trademe and buy a cheap smartvent then get quotes to install it from sparkies. There is so little difference between all the brands you might as well save some money. (on positive pressure ventilation that is)

Niel

3267 posts

Uber Geek
+1 received by user: 80

Trusted

#827363 28-May-2013 21:30

The heat recovery systems are a good idea to reduce wasted heat, but at most (if 100% efficient) will recover only half of the energy as the outgoing air will cool down halfway and the incoming air heats up halfway.

We have gone down the road of a large heat pump for the living space where we spend most of our time, and running an automatic dehumidifier in Winter. Houses are not sealed, my doctor says you do not need to pump fresh air in to breath. The ventilation system I'll install is the same as a heat transfer system, but the fan will run in the opposite direction. The reason for this is that heat transfer only works when you have a concentrated heat source like a fire place so that you can afford to loose some heat through the ducting - even insulated ducting has an R-value of less than 1 so any air drawn through ducting will cool down significantly and thus useless when you're starting off with normal room air temperature. What I'm going to do is draw air out of bedrooms and into the living space where the aircon will heat (cool) it, and air that is already heated (cooled) will be drawn through the hallway to the bedrooms. This will be done very soon, first had to do some landscaping jobs before Winter.

To reduce telemarketing calls you can do 2 things: 1) list your number on the "do not call" list mentioned earlier, and 2) reject anonymous phone calls (a feature included with the XNet VFX VoIP phone line we have). We get 1 call every few months, if that many, and had the same East-Auckland phone number for the last 12 years and listed in the phone book and have 3 cars + trailer on the vehicle information register.

You can never have enough Volvos!

Quic Broadband

Move to New Zealand's best fibre broadband service (affiliate link). Free setup code: R587125ERQ6VE. Note that to use Quic Broadband you must be comfortable with configuring your own router.

Niel

3267 posts

Uber Geek
+1 received by user: 80

Trusted

#827376 28-May-2013 21:47

evileric: To give you an idea I just checked the control panel (the system comes with air temp sensors) and the air in the lounge is being expelled at 20c (heatpump heated). The outside air being drawn in is 4c, but being warmed up to 17c and fed into the bedrooms. Obviously the warmer it is outside the better the recovery temperature. There is usually a 1-2c difference.

I'm not saying the heat recovery systems are useless, it is better than not having it, but the science says it is impossible that the (total) incoming air can be heated to more than the average between the inside and outside temperature. Unless the system is setup to blow less air in than what is blown out, so the incoming air is moving slower than the outgoing air and thus the incoming air gets to a temperature higher than the average of the two. But as you cannot suck a vacuum in your home, cold air will then also be drawn in through ventilation holes in window frames and gaps around doors. The net result is still that you recover (in perfect conditions) only half of the heat you are pumping out.

The issue with condensation on metal window frames is the metal. Should be PVC to get insulation (more than just an air gap). We also have aluminium and did not think it would be that bad as we did check for a thermal break between the inside and outside. Window frames also have mandatory ventilation slots where cold air can be drawn in and cool down the frame causing condensation. This is probably when PPV has a benefit, it forces warmer air out through the window vents rather than draw cold air in through them, so the frames do not cool down as much and you get less condensation.

Maybe we should add heating wires to our metal window frames?

You can never have enough Volvos!

mattwnz

20520 posts

Uber Geek
+1 received by user: 4798

#827414 28-May-2013 22:32

evileric: Hi there
Been a long-time lurker of Geekzone forums, so thought it was about time to give something back

Sounds like your problem with your aluminum windows and condensation was due to the frames not being thermally isolated. Having a thermal break in the frame will stop condensation forming on them, and then ventilating by opening the windows and using natural stack ventilation.

Niel

3267 posts

Uber Geek
+1 received by user: 80

Trusted

#827471 29-May-2013 06:31

mattwnz:
evileric: Hi there
Been a long-time lurker of Geekzone forums, so thought it was about time to give something back

Sounds like your problem with your aluminum windows and condensation was due to the frames not being thermally isolated. Having a thermal break in the frame will stop condensation forming on them, and then ventilating by opening the windows and using natural stack ventilation.

No it won't, my new double glazed aluminium frames locally manufactured have a thermal break but all of them get condensation (on the frame) when it is cold enough outside. The thermal break is not much as you still need the window to be structurally sound, basically it is just a thin rigid rubber seal. Condensation is certainly much less, but to stop condensation on the frame you need the insulation you get from PVC frames.

You can never have enough Volvos!

timmmay

20859 posts

Uber Geek
+1 received by user: 5350

Trusted

Lifetime subscriber

#827480 29-May-2013 07:41

I have one proper double glazed window, done during renovations, it's PVC. I've never seen condensation on the frames.

TinyTim

1058 posts

Uber Geek
+1 received by user: 167

Trusted

#827520 29-May-2013 08:54

Niel: The heat recovery systems are a good idea to reduce wasted heat, but at most (if 100% efficient) will recover only half of the energy as the outgoing air will cool down halfway and the incoming air heats up halfway.

Aren't you describing a fairly unsophisticated heat exchanger design? A good heat exchanger will transfer most of the heat.

Lenovo

Shop now for Lenovo laptops and other devices (affiliate link).

timmmay

20859 posts

Uber Geek
+1 received by user: 5350

Trusted

Lifetime subscriber

#827526 29-May-2013 09:00

TinyTim:
Niel: The heat recovery systems are a good idea to reduce wasted heat, but at most (if 100% efficient) will recover only half of the energy as the outgoing air will cool down halfway and the incoming air heats up halfway.

Aren't you describing a fairly unsophisticated heat exchanger design? A good heat exchanger will transfer most of the heat.

If you have incoming air at 0 degrees and outgoing air at 20 degrees, assuming equal volumes of air, they will come to equilibrium at 10 degrees. Without some kind of sophisticated device you can't easily get the outgoing air down to 0 degrees and the incoming air up to 20 degrees.

TinyTim

1058 posts

Uber Geek
+1 received by user: 167

Trusted

#827542 29-May-2013 09:23

timmmay:
TinyTim:
Niel: The heat recovery systems are a good idea to reduce wasted heat, but at most (if 100% efficient) will recover only half of the energy as the outgoing air will cool down halfway and the incoming air heats up halfway.

Aren't you describing a fairly unsophisticated heat exchanger design? A good heat exchanger will transfer most of the heat.

If you have incoming air at 0 degrees and outgoing air at 20 degrees, assuming equal volumes of air, they will come to equilibrium at 10 degrees. Without some kind of sophisticated device you can't easily get the outgoing air down to 0 degrees and the incoming air up to 20 degrees.

Wikipedia describes air to air heat exchangers with efficiencies of up to 85-99% (80% in HVAC), where efficiency = heat transferred (i.e. 100% means incoming air heated to the same temperature as the outgoing air).

timmmay

20859 posts

Uber Geek
+1 received by user: 5350

Trusted

Lifetime subscriber

#827544 29-May-2013 09:29

TinyTim: Wikipedia describes air to air heat exchangers with efficiencies of up to 85-99% (80% in HVAC), where efficiency = heat transferred (i.e. 100% means incoming air heated to the same temperature as the outgoing air).

If you have a lot of warm air and a little cold air, sure, I can understand that. But if you have equal volumes how can you get the fresh air up to the temperature of the stale air? My understanding is equilibrium is best you could achieve.

TinyTim

1058 posts

Uber Geek
+1 received by user: 167

Trusted

#827545 29-May-2013 09:36

timmmay:
If you have a lot of warm air and a little cold air, sure, I can understand that. But if you have equal volumes how can you get the fresh air up to the temperature of the stale air?

Presumably using a counterflow arrangement.

1 | 2 | 3 | 4 | 5 | 6