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Everything posted by JohnMo
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MVHR vs Air Con - if you had to pick one?
JohnMo replied to Indy's topic in Mechanical Ventilation with Heat Recovery (MVHR)
And it starts tomorrow! -
MVHR vs Air Con - if you had to pick one?
JohnMo replied to Indy's topic in Mechanical Ventilation with Heat Recovery (MVHR)
Are you a big building firm massaging the results. I installed MVHR and happy with the fresh air feeling every day. 5 years in shower silicone looks nice and white, so bathroom well ventilated. -
MVHR vs Air Con - if you had to pick one?
JohnMo replied to Indy's topic in Mechanical Ventilation with Heat Recovery (MVHR)
Definitely - vaulted ceiling are great. People seem to think they make a room hot and stuffy or takes loads of energy to heat up. But it all depends on you heat the room. High temp radiators, heat goes to fill the top of room first, so yes it does take a lot energy, air con in heating maybe the same. UFH gives a very even spread of heat, top of a vaulted room is hardly any warmer than anywhere else. Summer solar gain the heat can fill a big void above your heads first. -
MVHR vs Air Con - if you had to pick one?
JohnMo replied to Indy's topic in Mechanical Ventilation with Heat Recovery (MVHR)
But build in Scotland to airtightness better than 3 it's mandatory. -
I had one in 2012, was great for around 5 years, the gremlins started, replaced bit after bit as each one started to fail, then more expensive bits started to fail and then I chucked it to the recycling centre. 2000m² will need a good battery capacity, get one that is self guided doesn't need a wire guide around the lawn.
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MVHR vs Air Con - if you had to pick one?
JohnMo replied to Indy's topic in Mechanical Ventilation with Heat Recovery (MVHR)
I just went one step beyond you, now just do DHW heating via the immersion on a simple immersion timer. Energy used overall not much more than the heat pump. Long pipe runs, slugs of cold water... Big heating session when we have used plenty of hot water, ASHP is definitely cheaper, smaller top up heats immersion is cheaper, overall it balances out. You can also install a super simple system if you wanted. Two pipes to UFH manifold from ASHP and you have heating and cooling sorted. -
MVHR vs Air Con - if you had to pick one?
JohnMo replied to Indy's topic in Mechanical Ventilation with Heat Recovery (MVHR)
MVHR is ventilation. Aircon is heating and cooling, it's not ventilation. You need both ventilation and heating. MVHR doesn't solve the heating and Aircon doesn't solve your ventilation requirements. Your builder is talking out of his .... MVHR or another ventilation system is a must have. It's not something a heating appliance will replace -
Think you have chosen it, easy enough to do yourself.
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Independent battery storage comparison??
JohnMo replied to BotusBuild's topic in General Alternative Energy Issues
Home assistant uses the IP address and you can change anything you want from there, same as the Monitor app does. So fingers crossed. The phone app is useful to find the IP address, mine seems to have changed a few times, no idea why.- 29 replies
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- battery
- whole house
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All sounds dinky. My balcony structural engineer designed, was a combination of 10x2 and 6x2
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Yes all UFH plus one fan coil. I have found raising flow temp 1-2 degs higher than I thought was needed, at higher oat has allowed more controlled modulation, have had to use a high limit thermostat set at target house to kill the heat pump off though. The lower the flow temperature the higher the minimum output. It could be you are at or below min modulation and boiler is protecting itself, instead of switching off.
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Independent battery storage comparison??
JohnMo replied to BotusBuild's topic in General Alternative Energy Issues
Had an email the other day saying cloud services were now going to charge via a monthly subscription. Sort of raised a warning bell. Will do things other ways, locally via home assistant and or Monitor for GivEnergy Inverter.- 29 replies
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Those flow rates are higher than my heat pump, it's generally settling down to about 0.36m³/HR, most the time
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Isn't this why structural engineers exist? Plus with drops you should have a structural design certificate anyway. Other than that no comment
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MVHR & wet room windows… any thoughts on fixed vs opening?
JohnMo replied to fatgus's topic in Windows & Glazing
It may bring you presents if your unlucky. -
MVHR & wet room windows… any thoughts on fixed vs opening?
JohnMo replied to fatgus's topic in Windows & Glazing
I'm more worried about more wild stuff coming in for the night. -
You are going to have to pay to connect up your PV.
JohnMo replied to SteamyTea's topic in Environmental Building Politics
She has a lot to answer for, energy market (oil and gas given away) etc as well. Plug in solar, if you get a fee for registration, who will bother registering? Suggest no-one. -
MVHR & wet room windows… any thoughts on fixed vs opening?
JohnMo replied to fatgus's topic in Windows & Glazing
We have opening doors on to our decking in all bedrooms, but you can't really leave those open, an open window while sleeping, is very different from an open window for a sense of security. -
MEV is a single fan unit with all wet rooms feeding into a single unit and then to a single outlet through the roof. Get an intelligent one that alters fan speed based on demand, and install humidity activated extract terminals. Then add humidity activated trickle vents, for a fully demand operated ventilation system.
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People say the same for timber construction, which is standard building method in Scotland. No one has issue with finances or sales. External insulation has been given out free for ages by the government, so not seeing the issue there either. Personally I wouldn't do block or cavity build, it would be ICF or twin stud timber frame, as I could do both myself.
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What numbers do I need to size a heat pump?
JohnMo replied to Selfbuildsarah's topic in New House & Self Build Design
If your a new build that is pretty airtight with MVHR and decent insulation, unless the house is 400m² I doubt 7kW is correct, especially near Cambridge. -
Why MEV instead of dMEV if venting via roof. But that's another topic. Hybrid is fine as long as all the details are worked out and followed. Warm roof also fine as long as all details are worked out etc. Doesn't make either easy to do well You can do that, but you still need to fill between rafters at the wall to roof insulation gap and stop air movement and give continuous insulation layer.
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Insulation above roof is in theory easy to do. But you need to detail well, think about how you seal the gaps between the roof insulation and join to the wall insulation. If you rafter is 150mm high you have a gap 150mm to fill at every rafter. Why not through wall? Hybrid roof insulation Can be a recipe for disaster if you don't follow the rules and have a sound basis for construction.
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Or don't bother with cavity - block wall and external insulation? You can see exactly what is going on.
