Anyone else rethinking heat pump plans because of the heatwaves?

Martyn1981

https://forums.moneysavingexpert.com/discussion/comment/82105289#Comment_82105289

I followed the advice of Coastalwatch the pioneer (I believe) of A2A heating on the G&E board. He suggested something like this for the bathroom, and I got one. But leaving the bathroom door open when not in use is mostly enough to keep the room warm. But location will be important, ours is at the top of the staircase, where the hot air from below rises.

Our smallest bedroom, with a large cold north facing bay, is furthest from the stairs, but I just switch on a 400W oil rad for top up when in there, and that's enough.

I expected the kitchen to be the trickiest to heat, as it isn't 'on the route' for the warm air from the two A2A units. Plan was to add a hot air blower, but turned out that simply popping a 9in desk fan in the service window between the kitchen and the conservatory (with an A2A unit) is more than enough to heat the kitchen. It draws heat through nicely.

You could put an indoor unit in the kitchen, but we were advised not to by the installers as the filter and heat exchanger may injest cooking fats, reducing efficiency and being harder to clean.

TBF the warm air wants to spread out around the house more than I'd expected, but a big caveat, doors need to be left open, which might be an issue for some children/teenagers. But that said, we have to keep our bedroom door mostly closed (just enough room for dogs and cats to prevent complaints) to stop it getting too hot, as we pre-heat the house overnight on cheap rate leccy.

ed110220

https://forums.moneysavingexpert.com/discussion/comment/82105292#Comment_82105292

Hi Mart and everyone else,

Interesting to learn that there are heat pumps that do air to water for heating and air to air for cooling. I was aware that A2W existed for cooling, but as most of our CH pipes are in walls and floors etc and very inaccessible it would be impossible to insulate them so they would almost certainly attract a lot of condensation if used for cooling so I'd ruled that out.

So I thought my options were limited to either

Air to air - advantage gives cooling, disadvantage doesn't provide hot water so would have to keep the gas boiler which is getting unreliable, gas standing charge etc

Or air to water which gives DHW but not cooling.

Ectophile

https://forums.moneysavingexpert.com/discussion/comment/82105947#Comment_82105947

Or use cheap night rate electricity and an immersion heater. Part of my A2A idea was to fit a timeswitch to the immersion that's already there.

silverwhistle

https://forums.moneysavingexpert.com/discussion/comment/82105289#Comment_82105289

Same here, and haven't chosen a good time to do so! But I'm not bothering about my small kitchen where I'll be active with secondary heat sources. As for the bathroom I've got an electric towel rail similar to the one pictured above but I often forgot to switch it on and didn't notice.

As for hot water I've got an immersion which gets heated normally by spare PV energy and by March doesn't really need boiler input. Certainly well below the savings I hope to make from not having a gas standing charge. Last October I used 37kWh of gas and this March less than 20kWh, and even in November roughly half the gas cost was standing charge!

I only intend a two unit multi-split for a single occupancy 3 bedroom terrace, and the upstairs bedroom unit is really there for summer sleeping, with very occasional winter use. That is in the south though..

prowla

I considered an A2A system and even had an installation (Heatable) booked but the supplier said they had supply line difficulties and couldn't guarantee a new date for at least a month, so I cancelled it.

I may revisit once the current rush (ahem) cools down.

The great thing about a/c is that the peak time you need it for cooling is also precisely when the solar panels are getting loads of sun, so that's great; however it's the opposite in winter, in that you may need it for heating when there's no sun and the panels are covered in snow, so you're then effectively on a battery-only energy plan.

There are A2A system which heat too, but they can't both heat and cool at the same time, so a separate unit would be needed for water.

And that then begs the question whether it is better to go for an A2W system for the water and heating and thereby get the full grant.

The A2W systems have two issues: i. the outfdoor units are large and ii. they may need significant re-plumbing work doing on the house.

I've an appointment (a Heat Geek appointed installer) booked to discuss their options (minimum disruption) next week.

I could see myself having both systems this time next year.

Or alternatively I may still just have my trusty old gas boiler and tank plodding on.

QrizB

I'm planning to try my 12k BTU (3.5kW) portable split for heating once it gets cold enough (this heat can't last forever). Based on that I'll see whether a permanently installed 12k or 18k A2A makes sense for me.

My ground floor is about 60 sq.m. and largely open plan, so a single unit will have a fighting chance of heating most of it.

michaels

I suspect a non MCS A2A will be the same price as A2A with grant deducted.

This would then let you keep gas for hot water, sub 2C and rooms the A2A doesn't reach and use A2A the rest of the time and for cooling giving a really great cop and a nice fuel cost saving.

WE have been running our A2W in cooling mode with rads sized for 45c heating flow. It does help, keeping in door temps down by about 5c but this can still be unpleasantly warm. We have added PC fans to one rad and the also run ceiling fans to mix the air. Unfortunately our HP is not smart so we can't automatically adjust the flow temp to match the dew point and on 35c days the dp can vary between 12c and 20c with the latter resulting in much less cooling. Google suggested even before you get visible sweating there can be condensation in the poorly painted inner fin areas that are highly prone to rusting.

ed110220

https://forums.moneysavingexpert.com/discussion/comment/82106156#Comment_82106156

We've had the solar since June 2022 so I'm not under any illusion that it will help much with heating in winter. But with the batteries and Octopus Go tariff the day export rate is more than the off peak import rate, so perhaps counterintuitively you're better off maximising solar export and off peak import rather than self-consumption. Therefore it doesn't actually matter that the solar isn't producing at the same time as you need the electricity, and in fact it's better financially if it doesn't!

EricMears

https://forums.moneysavingexpert.com/discussion/comment/82106129#Comment_82106129

That's exactly what I've been doing since March.

Normally speaking, our house is heated with oil via a 'Heatbank' & UFH. When price of oil shot up after the little problem in Iran, I switched the Oil boiler off and heated the Heatbank with our log burner plus immersion heater running overnight at 7p/kWH (Octopus IOG) plus a couple of hours during day from battery system.. We supplemented that with an A2A unit to heat lounge area but of course the A2A unit was switched to cooling mode for the Summer.

Now pondering what to do for Winter if oil prices don't drop back to normal.

prowla

https://forums.moneysavingexpert.com/discussion/comment/82106156#Comment_82106156

So, the Heat Geek surveyor came and they've determined that my radiators are on a single-pipe system and so I need re-piping and thus the Zero Disrupt can't be done the quote is for over £11k (on top of the £7.5k grant).

My conclusion is that an A2W heat pump is not a viable option for me.