Benjseb

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So we had our 9kWp system commissioned on Friday, after it being on the roof of our holiday let for 3 months (but no mains supply!) Turned on Friday lunchtime and so far we’ve generated 120kWh. Not bad for one weekend! It’s been a mix of sun and clouds too. Heated up the DHW tank to 50c three times over now so the ASHP has been doing very little. We have this on 3 phase. Ive spoken to the installer and we’ve decided the Apollo Gem diverters aren’t ideal. As they are only single phase, it was pushing “excess” energy into the DHW tank, even when we were importing on another phase. So switching for a MyEnergi Eddi which will measure the net export across 3 phases. Now to play the game where we try and work out what appliances we can use below the current generation! Our OWL monitor has gone a bit crazy. Presumably as it can’t tell the difference between import/export so I have no way of telling what we’re exporting aside from watching the meter flash. But seems the Eddie has a decent app so can use that.

Finally installed and gone live We installed a 63amp submain to new holiday let that has 9kWp solar array with inverter then in the holiday let and the main house we have solar inverters which feed an immersion in both our DHW tanks theres also a secondary “overflow” output which will heat up our underfloor buffer tank Only went on at 12pm and generated 30kWh today so happy with that.

Well the holiday let is almost complete Today we turned on the Solar. So far generating about 4.5kW (8kWp system), not bad for a partially overcast spring day Weve got the solar on the holiday let roof, but then it also comes through our main house supply. 2 Apollo Gem optimisers, so the house runs off 1 phase, the other 2 phases power the holiday let and any excess is diverted to 3 water tanks: 2x DHW (one in holiday let, one residential) 1x Buffer tank for ASHP So if the hot water is already warm enough, the buffer tank will heat up which is useful for these shoulder months where it can be a bit chilly sometimes in the evening in the main house Hoping this will bring our £300/mo elec bill down! (All our heating, cooking etc is on elec as no gas)

yes it’s all stone and from the feel of it zero thermal break. We could secondary glaze I guess. I need to look at the options. We have the same in the lounge downstairs. They do tend to leak slightly in heavy driving rain too I wonder if secondary glazing is just delaying the inevitable. I shall find someone who knows a lot more than me about windows to take a look and give us a quote! Generally that part of the house must have been renovated at a different time. The rest is cosy You can see if the pic attached how there’s no/very little insulation on the inner stud wall in the lounge too (hot spot is TV)

Good point about the window surrounds. I had a quick peek behind a section of plasterboard about a year ago when some electrical work was being done. Seems the Kingspan insulation was “thrown in” ?? The other issue we have though is the stone mullions being about 5c so they attract any moisture in the air and over time start to go mouldy. When we moved in they were black! We cleaned them off and have lowered the humidity about 10% since but bring quite sensitive to mould I’d rather not have any surfaces that are that cold compared to the room. We’ve had a quite for replacements with a thermal break but I’m not convinced how much better they will be. And at £1500 a pop without glazing they are quite expensive. Seems that would require quite some effort to replace anyway so we were thinking it may just be worth putting a lintel in and using normal casement windows moving forward. And yes I see your point with the velux. We do have blinds already, but I think a shelf would work well. No chance of a radiator fan in the bedroom, the Mrs can hear a pin drop a mile off ?

So I took the plunge and purchased a FLIR One camera for my phone to investigate heat loss my suspicions were correct see image below. The rather yellow end of the house is our lounge and master bedroom. Clearly losing more heat than the rest of the building from inside I can also see some areas where the insulation is missing so next job is to pull the plasterboard off and reinsulate. If we can bear the mess! The original stone millions around the windows are like fridges too so may need to switch those for something with a bit less cold bridging going on.

What size ASHP is this (kW?)

We have two decent Triple column rads. The issue is they are both fed off a single 15mm flow before reducing to 8mm for the last 1m. So increasing Rad size won’t fix anything without sorting the pipes as there won’t be enough flow to support the extra rad size. So it’s a toss up between opening up the walls to run better Pipes, or insulate. And as both are disruptive I’d rather insulate and reduce the energy requirements. That’s my thinking anyway!

Looking at our Tado the lounge heats at approx 1/2 the rate of the rest of the house... about 2 degrees in 12 hours.

Yes that sums up our situation. We effectively have three areas/configs: * Downstairs on UFH. Works great at 35c and calls for heat say 40-50% of the time * Upstairs radiators. Calls for heat 10-20% of the time as warmed from downstairs. * Lounge with radiators. Calls for heat 100% of the time ? so obviously we need to address the lounge as that keeps the HP on all the time. And as mentioned we know this is due to poor insulation we need to address. we did stop the setback on the lounge as it takes hours to regain 2c. In contrast the UFH areas warm up quickly even at a flow temp 10c lower. just a pain the insulation to master bed (above the lounge) will be so disruptive.

I may do a few days on say 40c with it running all the time with a few days at 42 which would probably let it turn itself off for say 10-20% of the time and compare costs its all the parasitic costs like pumps etc which like everyone is saying, soon add up As we have a small buffer, we find that even when the stats don’t call for heat, the AS then runs for another 10 mins or so getting the buffer tank to its proper temp then by the time that’s sorted, stats call again! this is mainly due to us having a master bedroom with lounge below (approx 32sqm) Which are the only two rooms we didn’t tear down the ceiling and add loads of kingspan. As such the heat demand in those rooms are higher, and coincidentally are heated by large rads, so the combination means those rooms call for heat a lot more. Next job is to pull down the upstairs vaulted ceiling and insulate. But having only replastered and decorated last year, the Mrs is reluctant to cause loads of mess again!

It’s never struggled to get to the correct water temp. Remember it’s inverter driven so it’s probably only pushing out 30-50% of its output. Our UFH is only retrofit so doesn’t maintain the heat for as long. We have some nice stone walls that help with the thermal mass but I feel if we turned things off overnight we’d end up having to increase the Flow temp to get back up to temp in the morning. so that’s the question really. Is it always just about flow temp or is there an argument for slightly higher flow temp in return for the ASHP being completely off for a period.

Ps, this is for a 14kW Ecodan.

Hi all I’ve been operating our ASHP on the basis of keeping flow temp as low as possible. So I’ve been setting it low and when the room temp doesn’t reach the required setting, bumping up by 1c until we get there (now I have the compensation curve set between 39 and 45) Based in this, the ASHP runs 24/7 as it’s just matching the heat loss. It’s invertor driven so not running at full pelt, but does tend to tick along constantly. is the above correct or is there any merit in having the flow temp slightly higher so the heat pump turns off maybe 25% of the time? thanks Ben

Yes be good to see that info- o can do the same with mine which is a compatible sized property to see how they are performing

Hahaha love it ?

Things would certainly be easier without a boss who’s super sensitive to noise, light, etc! ill try ensuring the trickle extractor stays on (disabling the spur switch ?) and opening up the bottom of the en-suite door a little, in combination with velux on trickle and see how things go. I think it’s pretty unrealistic to live in an old house and not be willing to live with some form of compensation!

Yes very true. I guess my preference is to incorporate some more fresh air, rather than remove humidity from the air that isn’t moving much. Better health gains from the fresh air. I did look at PIV but with no loft it’s a PITA to fit and a bit of an overkill.

There’s 6-8l/s extraction in the bathroom. The envirovent extractor we have is annoyingly easy to flick into boost so may address this, shave a bit off the bottom of the door then it should be a steady trickle of air out. The issue I guess is that the air needs to come from somewhere so ideally we need trickle vents inside the bedroom ( otherwise it’ll draw from the landing and bypass the bedroom).. so it’s a battle between keeping those velux vents open vs the mrs being able to hear wildlife through them ?

yep I can do this on the en-suite. Good idea.

Due to the size of the room a small humidifier doesn’t really do anything unfortunately.

Already put the trickle extractor in. It’s a bit of a pain in that if it gets dirty, or the external humidity is high, it tends to stay in boost mode. So it works but it’s not ideal. I think I can definitely add a vent to the bottom of the en-suite door. The door into the landing is actually about 8” below the landing floor level so a vent would need to be halfway up the door which would look a bit rubbish (wouldn’t pass the MrsSeb test!)

Hi Our master bedroom is fairly sizeable (8m x 4m), some exposes stone and a small set of stone mullion windows when we moved in we realised there was very little ventilation and it smelt a bit musty. There was mould on the stone windows. we added 4 large velux windows to the ceiling, which means we can purge ventilate much better now and in summer often leave them open However in the winter they tend to get closed (most I can manage is to keep one on trickle vent) and as such the humidity sits around 5% higher than other rooms (55% vs 50%) I would like to get this down as I’m quite sensitive to mould spores so was thinking either: 1. Add a solar kit to the furthest velux from the bedroom door and automate it opening day 3 times a day for 15 mins. Approx £250 2. Replace the window panes within the million surrrounds to give an opening window and/or trickle vents. A few £100 for new panes it could DIY trickle vents but not sure how effective that would be. 3. Remove the stone mullions completely as they are a massive cold bridge (they sit around 8c despite the room being at 18/29c 24/7) and replace with wooden frames as per other windows. About £1000 for frames plus new windows, day £500. We don’t have any listed status so can do what we want. I guess we’re either removing the cold surfaces for the humidity to condense on, or ventilating more to reduce the humidity Any preference on the above from people’s experience? thank you!

That’s a pain. I’m not a fan of having a 4g transmitter in my house.