Browse Forums Heating, Cooling & Insulation 1 Jan 26, 2009 9:47 pm Hi,
I'm interested to see if anyone out there either has one of these systems or knows somebody with one and how effective they are for heating/cooling a house. We are looking at both as a possible option as they extremely cheap to run and have next to no C02 emissions. If anyone has info please state what type of home it is and features, eg. doubled glazed single storey house. Cheers, Bailey. Energy efficient custom built house - Moving In 3 Weeks Re: Anyone have a HRV System or Sunlizard System? 2Apr 20, 2009 11:31 pm Hi Bailey We too are considering a HRV system but are a bit dubious about whether it actually lives up to all the promises! Is there anyone out there who might be able to shed any light on this? Have read an earlier thread about whirlybirds but from what I can tell these provide a little more than whirlybirds. In case you are interested - we have the majority of our living area north facing, with a large under roof alfresco area. We have double glazed everything so we don't think that we will need any huge heating/cooling units, just something to boost on the more extreme days. Any suggestions? Regards Mel The secret of success is enthusiasm .... http://romseyherewecome.blogspot.com/ Re: Anyone have a HRV System or Sunlizard System? 3Jun 01, 2009 10:47 am We're having an HRV sysyem in our new place. We have spoken to the company at length about it (saw them at the Home Ideas Show) and they offered to give us some referrals. Maybe try that?? Him, me + 4 small people! ~Building our 7 star dream~ Re: Anyone have a HRV System or Sunlizard System? 4Jun 01, 2009 3:26 pm ownerbuilderromsey Hi Bailey We too are considering a HRV system but are a bit dubious about whether it actually lives up to all the promises! I am similarly dubious. This is simply an expensive 30 W solar powered fan (not a heater)
* PV cells have low efficiency as solar energy collectors (~ 15%) * Why would you bother converting solar energy into electricity to move hot air from one place to another. If you wanted to heat a room with poor solar access you might as well collect the solar radiation directly onto an absorber and blow it directly into the room. This would be far more efficient. * I could think of far better ways to use the money to decrease my energy usage than buy a device that could be replaced by a normal fan that costed less than 10c a day to run. Re: Anyone have a HRV System or Sunlizard System? 5Jun 04, 2009 2:01 pm Sorry dynomite ... I think these are pretty good products, each has a different system / use ... will summarize here: HRV / Solectair - I understand these products are pretty similar. They sit in your roof cavity and blow hot air (from the roof space) back into your house via ceiling vents, they work both on a sunny day, or on a cloudy day or at night ie where your roof space is hotter than your house (ie from heat radiating in from the sun or convecting up from the house). The solectair can be attached to your evap a/c ducts, and the HRV can also vent your hosue in summer if the roof space is cooler than the house. Creates penetrations in celing insulation Sun Lizard / Solar Breeze - work by heating up air under a collector and pumping in back in via a roof or wall vent. Can also be configured to provide additional cooling breezes in summer or coolr roof cavity. Smart Breeze - best for metal roofs with sarking these pull hot air from between roof and sarking and pump it back into the house, and vent this space in summer to keep it cooler. I think the HRV and Solectair are good in that they will work in almost any house, Smart Breeze best for metal roof with sarking and sun lizard or solar breeze where you have, say a cold south facing roof, with some thermal mass that you can use to heat up that room. They all will reduce heating & cooling bills by some %, and if you have some thermal mass in a well insulated house and can run these during the day, while not as effective as good solar passive design they will mean a warmer house to come home to. In terms of priority, nothing works better than good orientation, good insulation, draught sealing ... then these products. Re: Anyone have a HRV System or Sunlizard System? 6Jun 04, 2009 10:12 pm lambchoppa They sit in your roof cavity and blow hot air (from the roof space) back into your house via ceiling vents Are you aren't worried about air quality? My roof space is full of fibreglass and makes my eczema play up terribly. Why not a ceiling fan that just pushes the warm air near the ceiling back to the floor? Re: Anyone have a HRV System or Sunlizard System? 7Jun 07, 2009 7:52 am I don't quite understand why some like to breathe roof space air? I think this HRV or DVS guys should be done for false advertising Change is what we need! Can we? YES WE CAN!!!!! Re: Anyone have a HRV System or Sunlizard System? 8Jun 07, 2009 11:05 am Whilst good design is the best way - products like the lizzard etc are an effective way of increasing warm air into a less than ideal house layout - ie few north facing windows etc. I personally like this design. Sola Mate http://www.sola-mate.com/ Recently shown on the new inventors show. Due to the lack of thermal mass in the house, to gain the best advantage you need to make sure the house is well insulated, walls floors windows, no drafts etc - so the house retains the warmth that is gained during the day into the non sunshine periods of the day. hmm is that night time As for air from the roof space - not for me thanks. Re: Anyone have a HRV System or Sunlizard System? 9Jun 07, 2009 12:25 pm From what I can gather here, the main problem is breathing in the air in the roof space. I think people can see that using the roof space to provide winter day warming and summer night cooling does work. So, let's address the problem; getting the roof space clean. 1) Put sarking in. Not only does this improve the house insulation, but also keep the the roof clean 2) Ceiling insulation - put in something that does not create dust or cover it (maybe sarking could be used and you get a the double bonus of increasing insulation. And perform anyone mentions it, yes, mark where your support beams are for when your walking up there (or better still, install some walkways). Make you ceiling clean enough to live in and you can enjoy the beauty of a almost free winter heater and summer cooler. These only work for winter days and summer nights so combine it with the old favourite of thermal mass and you'll get past the "off" period. BTW, I don't know how old the concept is, but I mentioned that same concept over 2 years ago viewtopic.php?f=31&t=1611 (look at the 8th entry by yours truly) The concept is sound. We just need to make or roof spaces cleaner when doing anew build. Don't throw the baby out with the bathwater. Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Anyone have a HRV System or Sunlizard System? 10Jun 07, 2009 12:38 pm Casa - There have been commercial products around for many years - and with dust filters etc you can achieve cleanish air - as for volatile gases - hmm not sure I'd like poly or glass fumes being pumped into the house. - An issue with putting sarking under the roof is it will reduce the amount of heat that gets in there in the first place. Hence why I prefer the option of an external box - which is very efficient at warming and collecting cleaner air - and I suggest for a lot better bang for buck in the volume of heated air it produces. Re: Anyone have a HRV System or Sunlizard System? 11Jun 07, 2009 1:33 pm Yak_Chat, The key thing I see is that when building, you need to spend a little more to make things in the roof as clean as the rest of the house. This has got to be better than the external box. The other advantage of a clean roof is that if you ever need to go there for storage or work, it's a much more pleasant environment. The external box would be more efficient than the roof space. Let's say for argument sake that the external boxes are 75% efficient and the roof is only 20% efficient. Sounds like the box is ahead, until you realise that during winter days the exposed roof area is something like 4 times larger and during summer nights the roof is like 20 times larger in area. External box - winter = 75% x Area = 0.75 Roof space - winter = 20% x 4 x Area = 0.80 External box - summer = 75% x Area = 0.75 Roof space - summer = 20% x 20 x Area = 4.00 So the roof space is cheaper, looks better and performs better. Also the running costs are less since you need more fans with the external solution. The external units need a fan to force the winter warmth down into the house and in summer they need to push air up the panels against the natural flow. For the roof space the fans would still have to push air into the house, but with less pneumatic resistance (therefore lower power) and in summer, here's where it gets really good, you just open some vents. No one's going to market a roof based system, since there very little stuff to supply. People like to pay for stuff rather than ideas. The external boxes are good for established houses with dirty roofs, but if building new, it will cost very little to use your entire roof. And as I said over two years ago, Basix has got it wrong with insisting on light coloured roofs. Done properly, the most energy efficient roof is a black one. And they look soooo good. What do you thing? Cheers, Casa Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Anyone have a HRV System or Sunlizard System? 12Jun 07, 2009 2:29 pm Understand your thinking but how hot do you think the air in there will get? I suspect not as hot as that of a small well insulated external device with clear glazing and dedicated heat absorbing / transferring tubes. As for designing a house roof space to do this task - why not design the house properly to have direct sunlight in it anyway But I see the merit of your thinking. I see the external units better options as retro fit units that make bad houses better. and with good insulation, a solar powered fan - running all day moving the hot air into the house they are effective devices. as for using them as cooling devices - I don't think that is their area of key efficiency - I'd rather see people install cardiffair units and really cool the place down. http://www.cardiffair.com.au Lock the house up to stop the head getting in during the day - then use the cool night air to reduce the internal temp as the night arrives. My thoughts. Re: Anyone have a HRV System or Sunlizard System? 13Jun 07, 2009 2:58 pm The air temperature in the roof space will not be all that high, but the volume is enormous. If you multiply the roof space air temperature above internal temperature x volume, it will be far better than the external boxes. That is, the temperature may be lower, but the heat is greater. I agree that the roof systems, no matter what type, should be supplementary systems and that living area facing north, plenty of glazing on the north side, etc need to be in place first. Never heard of the cardiffair system, but it doesn't sound all that good. You're drawing outside air into your house during a summer day, which may be fine in north Queensland, but the last thing you want to do in anywhere below Queensland. My objective would be no ventilation during summer days and lots of ventilation during summer nights. The high thermal mass is what will carry the night cooling through the day. (And when that starts faltering late in the day, my earth tubes take over!). Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Anyone have a HRV System or Sunlizard System? 14Jun 07, 2009 6:07 pm Casa2 The air temperature in the roof space will not be all that high, but the volume is enormous. If you multiply the roof space air temperature above internal temperature x volume, it will be far better than the external boxes. That is, the temperature may be lower, but the heat is greater. I agree that the roof systems, no matter what type, should be supplementary systems and that living area facing north, plenty of glazing on the north side, etc need to be in place first. Never heard of the cardiffair system, but it doesn't sound all that good. You're drawing outside air into your house during a summer day, which may be fine in north Queensland, but the last thing you want to do in anywhere below Queensland. My objective would be no ventilation during summer days and lots of ventilation during summer nights. The high thermal mass is what will carry the night cooling through the day. (And when that starts faltering late in the day, my earth tubes take over!). And so we discuss apprpriate housing for each climate As for the volume of air - versus temperature - agree. So now we both need to do a practical test and see who's idea of a system works best - versus costs - and visual impact You've won the visual impact points already Re: Anyone have a HRV System or Sunlizard System? 15Jun 07, 2009 6:49 pm If you want clean hot air then people have achieved this with makeshift sunspaces using low-cost materials. All you need is a outside section of the house which has good solar access. Enclose it with a low-cost transparent plastic lining that traps the heat from the solar radiation and then pump the heated air into the house with a fan. It can double has a greenhouse. It is not really habitable (too hot when the sun is out and too cold when it isn't) but that's not its purpose.
http://www.builditsolar.com/Projects/Su ... spaces.htm Re: Anyone have a HRV System or Sunlizard System? 16Jun 07, 2009 7:41 pm dymonite69 If you want clean hot air then people have achieved this with makeshift sunspaces using low-cost materials. All you need is a outside section of the house which has good solar access. Enclose it with a low-cost transparent plastic lining that traps the heat from the solar radiation and then pump the heated air into the house with a fan. It can double has a greenhouse. It is not really habitable (too hot when the sun is out and too cold when it isn't) but that's not its purpose. http://www.builditsolar.com/Projects/Su ... spaces.htm This ones not going to win since: 1) It will cost a lot to build 2) It needs to be well insulated/isolated for cold winter nights 3) most people build to the limit for their block and this would quickly get bumped for more all year round living areas (or bedroom, study, larger garage, etc) Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Anyone have a HRV System or Sunlizard System? 17Jun 07, 2009 8:55 pm Casa2 dymonite69 If you want clean hot air then people have achieved this with makeshift sunspaces using low-cost materials. http://www.builditsolar.com/Projects/Su ... spaces.htm This ones not going to win since: 1) It will cost a lot to build From the link above, contributors have provided designs for as little as $50 of materials. http://www.rebelwolf.com/essn/ESSN-Feb2005.pdf http://www.builditsolar.com/Projects/Su ... nspace.htm http://www.builditsolar.com/Projects/Su ... lPorch.htm Re: Anyone have a HRV System or Sunlizard System? 18Jun 07, 2009 9:12 pm Yak_Chat Looks like a much more promising invention. Thermal efficiency is far better than using photovoltaics as a collection device. >70% compared to 15%. It is essentially a triple glazed sunspace on your roof. Re: Anyone have a HRV System or Sunlizard System? 19Jun 07, 2009 9:25 pm dymonite69 From the link above, contributors have provided designs for as little as $50 of materials. And how much for labour? Demolition August 2009, Construction Started September 2009, Completed December 2010 Re: Anyone have a HRV System or Sunlizard System? 20Aug 12, 2011 4:42 pm We have a HRV system and it's not all we were told it would be during the 'quotation process' - It has not reduced or stopped our condensation (in fact we now have mold growing on our curtains, and did not prior). At night it pumps cold air into the house, working against the heater. On sunny days when the roof cavity warms up, our home is filled with the stench of the roof cavity (old insulation filled with scent of previous (smoking) owners & staleness). It has not reduced sneezing, or the need for dusting. Now if we do not physically dry the condensation from the windows in the mornings, during the day when the house warms up, the water droplets vaporize throughout our entire home leaving condensation on all smooth surfaces - wood trimmings, mirrors, tapware, benchtops etc (this didn't happen prior). The 'burnt toast' mode is to remove cooking odours etc from within ones home, but the offending smell remains in our house for the duration it would have if we did not have the unit. We were told it is quiet and would never be heard, clearly it can be heard blowing and the motor running. And the ventilation pipes fell off our unit 6 weeks after installation, an inconvenient warranty issue we rectified ourselves as we are reluctant to have these people back in our home again. If we could go back in time, we would go with double glazing instead of wasting thousands of dollars on a product that has not stopped our initial complaint of condensation (which we were assured it would do). Thanks mate. Yeah good points! Leaning towards Option 3 to get a bit extra space in the cabinets but not going too crazy high (and expensive). Would require a mini… 13 42236 Hi All, I just wanted to close this topic out with an update. So we ended up agreeing to a number with the insurance company, and after an extensive amount of hand… 8 24909 You have mandatory building inspections and privately engaged building inspections. The difference between the two comes down to inspecting the building so it's safe and… 3 18866 |