Andehh Posted June 22, 2022 Share Posted June 22, 2022 Builder is looking at two seperate MVHR systems for our 250sqm bungalow, which is ''H shaped'' - entrance in the middle. I am keen for one to ensure the 6 medium bedrooms/study are properly balanced with the few large open plan 'living areas' in the opposite wing. All ceilings are between 3.2m and 4.4m so a lot of volume. Can anyone recommend any companies that can produce large single MVHRs that are worth speaking to regarding our slightly quirky property? Many thanks, Link to comment Share on other sites More sharing options...
joth Posted June 22, 2022 Share Posted June 22, 2022 20 minutes ago, Andehh said: Can anyone recommend any companies that can produce large single MVHRs that are worth speaking to regarding our slightly quirky property? You probably want to speak to a supplier, ideally one that will do the design for you, rather than the manufacturers. e.g.https://www.bpcventilation.com/free-estimate The Zehnder Q600 is one of the largest available which claims to support properties up to 350m2 so seems worth a look. 1 Link to comment Share on other sites More sharing options...
JohnMo Posted June 22, 2022 Share Posted June 22, 2022 There are benefits with two. Routing pipes and also the runs are shorter, so less pressure drop, lower running speed and less noise. Only part of house in boost instead of whole house, because you have a shower. Ours are split as, two spare bedrooms, one ensuite and our ensuite. We shower in our ensuite daily, so only the small system gets boosted. The rest of the house rarely in boost. Downside is two sets of filters. 1 Link to comment Share on other sites More sharing options...
Thorfun Posted June 22, 2022 Share Posted June 22, 2022 we have the Zehnder Q600 (not commissioned yet though but it is installed) and our designers configured it for 92mm ducts to give a larger flow rate to ensure we had the correct ventilation levels in our house which is quite large! couldn't have done it with the single unit with the smaller ducts and I really didn't want to buy, install, maintain 2 x separate units. Link to comment Share on other sites More sharing options...
Andehh Posted June 24, 2022 Author Share Posted June 24, 2022 Thanks very much all, good to have some system names known & good to know single big or two small are both worth exploring! Has anyone utilised a MVHR with Air COn systems, how have you managed them not acting against each other? Link to comment Share on other sites More sharing options...
JohnMo Posted June 24, 2022 Share Posted June 24, 2022 Aircon just circulates room air, heating or cooling it through a heat exchanger, similar to a fan assistance radiator. MVHR brings in outside and takes out stale air. Nothing to fight each other about, they do very different things. Link to comment Share on other sites More sharing options...
Rich97941 Posted August 3, 2022 Share Posted August 3, 2022 I'll be adding AC to an MVHR system. Although they do different things, I wondered if it was important to ensure that the MVHR didn't waste that expensive cool air and was thinking of a sort of reverse summer bypass so that when the AC was operational the MVHR would recirculate existing air rather than bring fresh hot air into the house. I had envisaged a simple valve arrangement that connected the outside supply and exhaust air ducts and blocked fresh supply. The control system would restore "normal" mvhr opeation in the the event of a boost demand due to high humidity etc. Has anyone done anything similar? Link to comment Share on other sites More sharing options...
JohnMo Posted August 3, 2022 Share Posted August 3, 2022 Think you may have lost the plot, making a simple reliable ventilation system in to something it's not. Sounds like a recipe for failed ventilation system, that also does little or no cooling as the flow rates are way to low to be effective. 1 Link to comment Share on other sites More sharing options...
Andehh Posted August 3, 2022 Author Share Posted August 3, 2022 Risk of Air Con is you turn it on during the day and cool the rooms down, but the MVHR system naturally pumps that cool air out the house and brings back in warm external air? We have very high ceilings everywhere, so I suppose there will be a benefit of the warmer air rising to the top (vents) and being extracted, whilst the cooler air sinks lower? I think i will work on the assumption that on the hottest of days, I will turn the MVHR down/off and turn AC on everywhere. Then when I turn the AC off in the evening, turn the MVHR back on. For those handful of days a year when we hit record temps, ill just add it to my routine of closing curtains to block out the sun, and isolate the air inside the house manually. Not sure what others do in these situations? Link to comment Share on other sites More sharing options...
Conor Posted August 3, 2022 Share Posted August 3, 2022 Just now, Andehh said: Risk of Air Con is you turn it on during the day and cool the rooms down, but the MVHR system naturally pumps that cool air out the house and brings back in warm external air? We have very high ceilings everywhere, so I suppose there will be a benefit of the warmer air rising to the top (vents) and being extracted, whilst the cooler air sinks lower? I think i will work on the assumption that on the hottest of days, I will turn the MVHR down/off and turn AC on everywhere. Then when I turn the AC off in the evening, turn the MVHR back on. For those handful of days a year when we hit record temps, ill just add it to my routine of closing curtains to block out the sun, and isolate the air inside the house manually. Not sure what others do in these situations? Nope. The MVHR heat exchanger works both ways. As long as the bypass is closed, you'll be cooling the fresh incoming air with the extracted air. You should be able to set the thresholds for the bypass opening and closing in the unit. Keep it simple. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted August 4, 2022 Share Posted August 4, 2022 On 24/06/2022 at 14:13, JohnMo said: Aircon just circulates room air, heating or cooling it through a heat exchanger Not the A/C units I had back home in the West Indies. I think it really depends what you want, and terminology differs. From my understanding A/C conditions the air i.e. controls humidity, temperature and replacement. The units sold in the UK are after just coolers and heaters, they don't change the air, so the AH stays the same, with the RH varying with temperature. Fitting cooling and heating to MVHR is, in my understanding, air conditioning. If it shifts enough volume is another matter. Link to comment Share on other sites More sharing options...
JohnMo Posted August 4, 2022 Share Posted August 4, 2022 But if the comment is applied to post above mine, where the inlet of the MVHR is to blocked, so it becomes a recirculation system, it is no longer MVHR and due to the flow rates a rubbish Aircon unit. So not fit for purpose. In a residential setting I have never seen Aircon that replenishes the air, just moved it through a heat exchanger with a fan unit. Link to comment Share on other sites More sharing options...
SteamyTea Posted August 4, 2022 Share Posted August 4, 2022 19 minutes ago, JohnMo said: Aircon that replenishes the air We had AirCo units in all the company housing. A big brown box though the wall, water dropped out the back. Two heat exchangers in them. The cold side was 'outside' to dehumidify, then another 'inside' for temperature control. Fan and compressor wedged between them. Good units, only had one go wrong in 4 years, sounded like an elephant with hiccups. I suspect the name AirCo was a local rebranding, for the French and Dutch West Indies, of someone else's unit, probably Carrier. Link to comment Share on other sites More sharing options...
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