Nickfromwales Posted March 27 Share Posted March 27 On 23/03/2024 at 22:37, CalvinHobbes said: So why should I do it? Expand Cooling. 2 Link to comment Share on other sites More sharing options...
Nick Laslett Posted March 28 Share Posted March 28 On 27/03/2024 at 23:42, Nickfromwales said: Cooling. Expand My build is taking me forever, so I have no actual facts or data to share. When I first came to BuildHub and started this journey, the challenge of cooling kept on coming up. Insulation and an airtight build mitigated the heating requirements, but due to solar gain, how did you tackle cooling. PPHP modelling, window shading these were the go to advice. Actual air conditioning if you could accommodate it. Then in amongst all this talk you discover an ASHP can be run in reverse and provide cooling. Back in 2019 there was some debate about if this wasn’t allowed by RHI or MCS, some ASHPs didn’t allow cooling or had the feature locked. For me this sounded like a good cooling solution. I was going to build an ICF house and have a poured concrete 90mm thick 1st floor. So I installed wet UFH in the first floor expressly for the cooling. The concrete floor was now not just an extravagant way to have a solid, non-creaky, sound proof floor. It was now my cooling block for the bedrooms. Unfortunately, I’m still building so have no idea if this approach will work. I also went with 70/30 tinted glass on the windows to help with the solar gain. And I’m putting the cooling module on my MVHR, which doesn’t seem very popular or value for money, or even effective! So @Nickfromwales one word advice might seem a bit cryptic, but to me it is classic Buildhub. 2 Link to comment Share on other sites More sharing options...
Conor Posted March 28 Share Posted March 28 We find slab cooling with ASHP very effective, even if it's only needed once a year or so (in northern Ireland so daytime temps rarely in the high 20s and nighttime usually in low teens) 1 Link to comment Share on other sites More sharing options...
JohnMo Posted March 28 Share Posted March 28 On 28/03/2024 at 07:33, Conor said: We find slab cooling with ASHP very effective, even if it's only needed once a year or so (in northern Ireland so daytime temps rarely in the high 20s and nighttime usually in low teens) Expand Us also. Not as good as Aircon, but does knock a couple of degrees off when needed. If you have PV generally free to use also. 1 Link to comment Share on other sites More sharing options...
Stones Posted March 28 Share Posted March 28 I'd also suggest comfort comes into this, and what type of heat you want. How an A2A delivers vs an A2W via UFH. I personally dislike warm air being blown around by an A2A, but when on holiday, appreciate the cool breeze of aircon. Heat delivered via UFH from our A2W gives a nice steady even temperature in house (with the added benefit A2W provides my DHW needs as well). But the cooling is less effective as it takes longer (albeit very pleasant when up (down?) to temperature. I think A2A are fantastic in large rooms / open spaces, less so in small(er) rooms. Like everything else, there are trade offs, and individual lifestyle requirements, and house location / design all play a part. 1 Link to comment Share on other sites More sharing options...
Cooeyswell Posted March 28 Share Posted March 28 On 27/03/2024 at 23:42, Nickfromwales said: Cooling. Expand As quoted by our representative from the sunny uplands of southern Wales. I'm living in a Passive spec build in a northern land - cooling ain't an issue. Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 28 Share Posted March 28 On 28/03/2024 at 22:28, Cooeyswell said: As quoted by our representative from the sunny uplands of southern Wales. I'm living in a Passive spec build in a northern land - cooling ain't an issue. Expand A Passsive spec build? Please elaborate... Depending on how far north, your PHPP may have specified that you wear thermal undercrackers. Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 28 Share Posted March 28 On 28/03/2024 at 07:30, Nick Laslett said: So @Nickfromwales one word advice might seem a bit cryptic, but to me it is classic Buildhub. Expand I am a man of few words... until 2 pints go in and then you can't shut me up Give me a slightly cold home and I'll pop a blanket over me, but give me a warm house and I'll kill everyone within a 50m radius. 3 Link to comment Share on other sites More sharing options...
joe90 Posted March 28 Share Posted March 28 When I did my build I was told by many here that my south facing 10m conservatory with bifolds into the house would overheat but frankly in the several years I was there it never got hotter than a good holiday in the south of France, (which many pay good money for) and during the shoulder seasons and even mild winter days was a lovely place to be. 2 Link to comment Share on other sites More sharing options...
Cooeyswell Posted March 28 Share Posted March 28 On 28/03/2024 at 23:09, Nickfromwales said: A Passsive spec build? Please elaborate... Depending on how far north, your PHPP may have specified that you wear thermal undercrackers. Expand Passive spec- 0.1U-0.12uU in all directions, 0.15U windows, MVHR etc. The usual stuff. I lived outside Chepstow for many years. At no point did I encounter Welsh cooling undercrackers, neither has anyone here suggested the application of Welsh crackers (under or over) as a cooling mechanism. I look forward to being enlightened. Link to comment Share on other sites More sharing options...
JohnMo Posted March 29 Share Posted March 29 On 28/03/2024 at 22:28, Cooeyswell said: As quoted by our representative from the sunny uplands of southern Wales. I'm living in a Passive spec build in a northern land - cooling ain't an issue. Expand I live at in NE Scotland and use cooling, the main reason for getting a heat pump was for cooling. Doesn't really matter where you live if you have biggish windows for the view, you will get over heating. On 28/03/2024 at 23:20, joe90 said: 10m conservatory with bifolds into the house would overheat but frankly in the several years I was there it never got hotter than a good holiday Expand So about 30 degs? Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 29 Share Posted March 29 On 28/03/2024 at 23:27, Cooeyswell said: Passive spec- 0.1U-0.12uU in all directions, 0.15U windows, MVHR etc. The usual stuff. I lived outside Chepstow for many years. At no point did I encounter Welsh cooling undercrackers, neither has anyone here suggested the application of Welsh crackers (under or over) as a cooling mechanism. I look forward to being enlightened. Expand Did your PH designer specify little windows and minimal southern glazing etc? Shading too? Most Passiv spec dwellings get very uncomfortable in the peak summer period. I’m about to start a certified PH build for a client, and we identified early on (on paper) that, for at least 35 days of the year, it would be outside a survivable temperature for the residents (PHPP done) so absolutely couldn’t be built without cooling having being introduced by design; as a mitigating measure to demonstrate that this had been addressed. PH architect suggested A2A A/C and also that the A/C got used to offset the opposite effect, where for 18 days (more imo) there would be a requirement for auxiliary heating. Suggestion was to pull out oil filled rads and heat the spaces independently to suit. Client found this out only after I highlighted it, and they weren’t very impressed. Lots of back-pedalling and talk of cross / purge ventilation and so on. If you’re managing without mechanical cooling I am equally curious, but house location / orientation / shading et-al and the micro-climate all play very large roles so defo ‘possible’ to design this out (solar reflective glazing is another Ace to keep up one’s sleeve). Link to comment Share on other sites More sharing options...
Iceverge Posted March 29 Share Posted March 29 On 25/03/2024 at 10:23, joth said: Be very wary of those sort of claims: the people making them are often highly invested (financially and emotionally) to push the performance of their building. Also just because one PH building does not need active heating it means nothing for the next. Expand Yes. Been there done that. You need if you want a warm house you need a heat source. Perpetual energy machines don't exist. Link to comment Share on other sites More sharing options...
Sparrowhawk Posted March 29 Share Posted March 29 On 29/03/2024 at 08:06, Nickfromwales said: I’m about to start a certified PH build for a client, and we identified early on (on paper) that, for at least 35 days of the year, it would be outside a survivable temperature for the residents (PHPP done) so absolutely couldn’t be built without cooling having being introduced by design; as a mitigating measure to demonstrate that this had been addressed. PH architect suggested A2A A/C and also that the A/C got used to offset the opposite effect, where for 18 days (more imo) there would be a requirement for auxiliary heating. Suggestion was to pull out oil filled rads and heat the spaces independently to suit. Client found this out only after I highlighted it, and they weren’t very impressed. Lots of back-pedalling and talk of cross / purge ventilation and so on. Expand Sounds like this PH architect has designed to the letter of the certification and not to the spirit. Unless the clients have imposed limitations that make it impossible to design out the overheating. Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 29 Share Posted March 29 On 29/03/2024 at 16:48, Sparrowhawk said: Sounds like this PH architect has designed to the letter of the certification and not to the spirit. Unless the clients have imposed limitations that make it impossible to design out the overheating. Expand In a nutshell, yes. Way OTT approach tbh. Just tricky when I’m trying to work with a client and act in their best interests and also not throw someone under the bus (when they’re genuinely doing what they think is the best job they can…..). Yay. 🥳 Link to comment Share on other sites More sharing options...
MikeSharp01 Posted March 30 Share Posted March 30 On 28/03/2024 at 23:27, Cooeyswell said: 0.15U windows Expand Wow - How is that achieved? I thought PH windows were 0.8 or better - ours are 0.78. Not sure how you could construct a .15 window you can see through. Link to comment Share on other sites More sharing options...
SteamyTea Posted March 30 Share Posted March 30 On 30/03/2024 at 06:33, MikeSharp01 said: Not sure how you could construct a .15 window you can see through. Expand Vacuum in the gap maybe. Link to comment Share on other sites More sharing options...
JohnMo Posted March 30 Share Posted March 30 On 30/03/2024 at 08:46, SteamyTea said: Vacuum in the gap maybe. Expand Typo maybe? Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 30 Share Posted March 30 On 30/03/2024 at 08:50, JohnMo said: Typo maybe? Expand Defo. Norrsken’s best offering doesn’t go much lower than 0.7. Let’s wait for @Cooeyswell to clarify. Link to comment Share on other sites More sharing options...
Cooeyswell Posted April 2 Share Posted April 2 On 30/03/2024 at 08:54, Nickfromwales said: Defo. Norrsken’s best offering doesn’t go much lower than 0.7. Let’s wait for @Cooeyswell to clarify. Expand Sorry folks that number was pulled from memory - and was clearly wildly incorrect. The average window U-value is 0.9 (Rational Auraplus, Triple glazed, magic coatings etc.) The house is South facing, Coastal and Northern. Overheating has not been an issue while we have lived here. Salt deposits on the windows provide all the shading we need 🙂 Not sure how PHPP handles this. 1 Link to comment Share on other sites More sharing options...
Kelvin Posted April 2 Share Posted April 2 On 30/03/2024 at 06:33, MikeSharp01 said: Wow - How is that achieved? I thought PH windows were 0.8 or better - ours are 0.78. Not sure how you could construct a .15 window you can see through. Expand Ours average 0.78 too. Link to comment Share on other sites More sharing options...
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