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Thread ID: 143041 2016-11-05 07:50:00 Home Ventilation - HRV vs DVS bk T (215) PC World Chat
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1428402 2016-11-07 02:49:00 ..........And then there are clothes driers that vent into the room, difficult to understand how any manufacturer could ethically design and sell such abortions :badpc:


Edit: and how many people with HRV/DVS have internally venting driers ??????????????? 		Terry Porritt (14)
1428403 2016-11-07 03:33:00 ..........And then there are clothes driers that vent into the room, difficult to understand how any manufacturer could ethically design and sell such abortions :badpc:


Edit: and how many people with HRV/DVS have internally venting driers ???????????????
Perhaps the people who buy that sort of driers are the persons that should be living in a swamp. Possibly they are the same people that put on an electric heater and surround it with racks of wet laundry in their lounge? Fortunately the punishment for this sort of thoughtless performance lands pretty close to the culprit.
True greenies will be recognised as those who only exhale once they are outside 		R2x1 (4628)
1428404 2016-11-07 03:37:00 Exactly, that is how the systems work. Inside temperature equals window temperature equals outside temperature(more or less)............ergo: no condensation.

Works well if you don't mind being cold. It's just physics, dew point and all that.

We were led to believe the "warm air" in the ceiling space would be chasing the cold air out through the areas around the windows, rofl. Ours was a tile roof, cold up there in winter and bl**dy hot in summer.

The old open fire was the story, warmed the whole inside area except for back porch, laundry and bathroom.

A wetback (not the Mexican type) to heat the water and having to run hot water off at the farthermost tap was a bugbear.

lurking.

Ps. physics was my worst subject in high school.

lurks. 		Lurking (218)
1428405 2016-11-07 05:09:00 To be a bit more serious, there is quite a good BRANZ site that describes ventilation systems, and heaps of other stuff

www.level.org.nz

Reinforcing what pctek says about older homes:
"Houses built in the last few decades of last century typically had infiltration rates around 0.3 ach, with houses built before 1960 having three times this much. These older homes provide the required ventilation just through their ‘air leaky’ construction. "

HRV is discussed here: www.level.org.nz

Some people who have the systems say they work well in removing condensation, others who have had systems installed say they don't, so take your pick.

These systems are only half the story, as they don't intrinsicallyprovide heating, so if the air in a house is being changed say 3 times an hour by bringing outside air, that air has to be heated.

If it is frosty and the outside air is 0C very roughly the extra heating required is going to be around 1kW (according to my sums) for a typical house on and above the heat required to maintain a steady 20C.

Energy = mass flow x specific heat x temperature change You can get all the parameters like air density and specific heat and units conversions via Google.

1litre/sec =0.001m³/sec

density air at 20C and 1 atmosphere = 1.2kg/m³

specific heat of air at 20C , 1atmosphere = 1kJ/kg°K 		Terry Porritt (14)
1428406 2016-11-07 17:15:00 ..........And then there are clothes driers that vent into the room

Edit: and how many people with HRV/DVS have internally venting driers ???????????????

I do.
Had it for 35 years now. Brilliant machine.

Of course, it lives in the garage, not keen on fluff being fired around the room...........never mind the humidity. 		pctek (84)
1428407 2016-11-09 06:28:00 Roof space - that's where they install them, no roof space, nowhere to install. Also the whole point is to use the warm air trapped in the ceiling to warm the incoming fresh air with a heat exchanger.


depends on your situation.
with the rather high humidity here it takes a lot longer to dry a place out.
hence i have to keep windows open all day long.
btw did have a humidity meter and it often took about half a day with all doors and windows open.

the best thing i find is ventilate little but often and don't let the moisture build up.
the other factor is heating. my place gets a lot of sun. good heat plus some ventilation = dry home.

ventilation and heating are opposites. to ventilate its going to get cold.
however i think you can get around that a bit.
you want to keep the heat of the day in as much as possible. then ventilate at night or early morning when outside air is at its coldest. its cold but dry. that way you need a lot less air. 		tweak'e (69)
1428408 2016-11-09 06:34:00 To clear a windscreen quickly, shut off outside air, turn on AC. If it's gets too cold turn on heating, to give warm dry air in the car, same principle for a house, but it takes energy, can't escape that.

actually its turn on outside air. outside air is typically drier than whats in your car.
replacing humid air with drier air is far quicker and cheaper to do. ie blow in dry air, push out the wet air.

i have a single cab ute for work. worse thing ever for condensation. we are big sweaty blokes crammed into a small cab. windows fog up real fast.
ac on, heat on and outside air. fastest window clearing you can get. 		tweak'e (69)
1428409 2016-11-12 04:33:00 From my own experiences, UNWILLINGLY repeatedly dealing with HRV's utterly unethical marketing and sales team, I would say the only way I would ever deal with HRV is if I was dealing to them with a baseball bat and a shotgun.

If I saw and HRV person in a life threatening situation - I'd give them a push to their death.

Serious pissed with this company and its people. They are only focused on an immediate sale. Cash rules. Service and morality doesn't. 		Paul.Cov (425)
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