selfbuild17 wrote: » Plenty of people do it but it’s not recommended. Current building regulations mean that you will be putting a lot of money and effort into making the house well insulated and airtight. You also obviously also must have reasonable ventilation in the house so that it’s comfortable and safe. A heat recovery system provides continuous background ventilation without losing much heat/energy in the process. If you don’t install one (or DCV or equivalent) you will have to provide background ventilation with old fashioned room vents or homes in the wall. They are difficult to control, cause bypassing of your expensive insulation and airtightness measures and create unwanted draughts. It’s the equivalent of buying an expensive luxury car and trying to save a few quid by excluding the AC as you can crack the window open instead
teednab-el wrote: » If you can open windows is that sufficient or have vents in the house instead? You can't open the windows with heat recovery system i was told. I be against not being able open your windows in the house. Maybe im wrong in saying that?
893bet wrote: » The difference is you don’t need to open windows when you have MVHR. You can open then with MVHR but it defeats purpose.
teednab-el wrote: » You can't open the windows with heat recovery system i was told. I be against not being able open your windows in the house. Maybe im wrong in saying that?
knipex wrote: » Of course you can. Nothing physically stopping you opening your windows. BUT Why would you need to ? People open windows to let in fresh air or to let out moisture. A Heat recovery system will provide fresh air. As I said you can open the windows all day if you wish, the heat recovery system will not care but you in winter you will be letting out all that heat and in summer you will be letting it in.
knipex wrote: » Why would you need to ? People open windows to let in fresh air or to let out moisture.
Nonoperational wrote: » It doesn't cool much. You can set a bypass mode but I still open the windows wide on summer nights. Certainly no reason not to get it in an A rated house.
teednab-el wrote: » 1. If you can open windows is that sufficient 2. or have vents in the house instead? 3. You can't open the windows with heat recovery system i was told. 4. I be against not being able open your windows in the house. 5. Maybe im wrong in saying that?
BryanF wrote: » 1. No. Refer to building regulations 2. Yes in each habitable room, with mech vents in all wet rooms - MHRV takes care of this. 3. Horse S... 4. Agreed. Required for fire safety. 5. Seek professional advice
teednab-el wrote: Does the heat recovery systen act like the a/c in a car? Am i correct in saying that?
teednab-el wrote: Is it worth the 8000 euro or is it a gimmick? Im hearing mixed views about it.my builder told it wasn't worth the money. Then other people swear by it so i just dont know.
teednab-el wrote: If the house gets too warm and you open windows with the HRV and its still warm. How do you control that then to cool the house? You say you dont lose heat with the HRV but if you really want to cool down the house we will say in very hot weather what do you do? The windows are open but the heat isnt reducing because of the HRV? Genuine question.
teednab-el wrote: Do you need room allocated in house for HRV? Can it be installed before house reaches ground level. If I were to change my mind about it?
teednab-el wrote: » Is it worth the 8000 euro or is it a gimmick? Im hearing mixed views about it.my builder told it wasn't worth the money. Then other people swear by it so i just dont know. If the house gets too warm and you open windows with the HRV and its still warm. How do you control that then to cool the house? You say you dont lose heat with the HRV but if you really want to cool down the house we will say in very hot weather what do you do? The windows are open but the heat isnt reducing because of the HRV? Genuine question.
runawaybishop wrote: » 8000 sounds very pricey. It's a very simple job and a good unit is not expensive. Shop around. The summer bypass will help cool the house down but you can't put in a mountain of insulation and no cooling and expect a house to be cool in the summer. You can just open a window if you want.
BryanF wrote: » This is the second thread where you’ve stated you’re at sub-floor level. Thats kind of alarming with the questions being asking.
teednab-el wrote: » Will the answers to these questions determine if i should install the HRV or not for you? If so il provide the answers.
dellas1979 wrote: » Hi OP, I have a beam system (MVHR)/air to water pump/UFH. Am getting subfloor tomo/concrete poured (windows/roof/slabbing/first fix plumbing/elec done). I chose to have this as the house is so airtight. Well, there wasnt really an option not to as on first airtightness test it was 1.4 air changes per hour. And that was before floor and slabbing was done. Passive house is 0.4 air changes per hour. I have a BER assessor (and architect) who look into this for me and advise. The architect couldnt advise - was the BER assessor. As am not a builder, I do have times when I need the information broken down a bit more to enable me to understand. There is also a very good facebook forum to ask these questions (PM me if looking for info). But anyways, basically, I have an airtight box on my hands. How do I get air into it and out of it (efficiently)? Now, my house was designed with these internal vents (they are in the ceiling as ducting needs to be done up stairs and downstairs). And it needs to be planned out by a specialist - not the builder or you going "yep-put a vent in here". Usually, it extracts bad air from kitchen and bathrooms (as these rooms have most moisture) and converts it to heat, and fresh air pumped in around the rest of the house. If you dont put it in such an airtight house, the house is at risk to moisture and damp and stale air. Edit: I have to say/ask also, you have a mortgage I assume. So even if this is to save money, the bank have a certain amount (on your costings form) attributed to this system. I wonder then how would you get this money? i.e., architect/eng signs off the work/material to be paid to builder. I wonder how that could work out for you in this case. I guess you just dont drawn down the 8k for the unit.
Lumen wrote: » I found this article quite useful. The PH+ guide to heat recovery ventilationhttps://passivehouseplus.ie/magazine/guides/the-ph-guide-to-heat-recovery-ventilation
Metric Tensor wrote: » OP - you need a ventilation system. Modern houses are built to such a high standard you can't rely on draughts to get rid of stale air and replace it with fresh air. The "heat recovery" part just makes sure that exhausting the stale air from your house isn't wasting all the money you spend on heat. Openable windows are still mandatory for purge ventilation as they always have been. If you need to change the air in any room quickly in an uncontrolled manner you always opened windows and will still do so. For gradual background ventilation that used to be provided in a half arsed way by a hole in the wall of each room you now have a designed system to do it instead. In the odd days in summer where the temperature is hotter outside than inside your ventilation system should have a "bypass" that prevents the temperature transfer part of the system. This is not present or poor on some cheaper units - so do your research. Your builder is almost certainly not qualified to advise on the above. The person who designed/specified your dwelling air tightness and ventilation *might* be in a better position - hence the questions BryanF asked. There's an increasing push in all elements of life to count everyone's opinion as equal. They are not. Just like you wouldn't let the guy at the pub prescribe you medication you shouldn't let him design your house either. Filter bullsh!t advice from qualified advice.
teednab-el wrote: » It was my builder who said day one that there was no need for the hrv.
