Portable split air to air

QrizB

I wasn't intending this to be a diary, but here we are 😀

Portable split diary, day four(?).

Today was the hottest day yet. My outdoor temperature sensor (in a shady spot) got to 34.5C. Indoors we got to 25C or so, then briefly exceeded 26C during the Saving Session aircon shutdown before dropping back below 25 over the next hour.

Energy-wise, it's also been the highest day of the period. We're currently around 15kWh and are likely to exceed 16kWh by midnight.

Tomorrow's forecast to be cooler, however the Met Office have extended the red weather warning to include Friday (a smaller area of England, but it still includes me).

Looks like the weather might finally break on Saturday, thank goodness.

TroubledTarts

It's a good benchmark for what these units are capable of and their energy use with this very hot weather for June we are having.

We are about to see 36-38oC here today so the upstairs unit will be on all day with 3 fans circulating the cool air.

QrizB

Portable split diary, day five.

Yesterday finished with 16.54kWh used.

Today's weather didn't peak quite as hot as yesterday, thank goodness, but overnight was still hot, the early morning minimum was still high, and my brick house is thoroughly heat-soaked. Plus no hour-long shutdown as Octopus didn't run a saving session. As a result of this it's been the most expensive day of the week in terms of energy use.

As I write this, just after 10pm, my energy monitoring plug is saying that we've used 18.4kWh and the split is still pulling 800 watts. I don't think we'll get to 20kWh but it's going to be close.

However the split has continued to do its job. My bedroom is at 23C, the downstairs hall is 24C, and the dining room (where we've recently finished dinner) has just touched 25C. I'm very happy with this, as are the other members of my household.

I'm going to leave the split running for now, but the forecast for tomorrow has early-morning temperatures dropping below 20C for the first time since Tuesday morning. If I'm up early enough I might shut it down then and try some natural ventilation instead.

Hope everyone else has been coping with the weather; it looks like the worst is behind us.

NedS

Ouch, 20kWh is as much as I use to heat my house in January.

It's a good job you will hopefully only need AC for a few days per year, or do you plan on running it outside of extreme weather events?

QrizB

Ouch, 20kWh is as much as I use to heat my house in January.

Power demand must've decreased after 2200, as we "only" got to 19.51kWh for the full day.

But I agree; that's a lot of electricity to use in one day.

It's a good job you will hopefully only need AC for a few days per year, or do you plan on running it outside of extreme weather events?

Looking at the current forecast, once today is behind us I should be able to switch it off and stay comfortable for most of the coming week:

Last night I happened to be awake at 0300 and realised that outdoor temperatures had dropped below 20C, so I shut the split down (it was drawing about 300 watts) and opened a few windows to let national convection do its thing.

It was back above 20C at 0800 (and rising) so the split's back on now.

matelodave

Some really useful info - thanks

Martyn1981

Just checked our cleverer A2A, which has wifi and data, and that shows energy consumption for the days in use rising from 3kWh through 5, then almost 10 then 5 and 3 again. During the peak, we also had the second one on, so possibly a doubling of the 5kWh, so back to 10kWh overall. That's ~£1.20 in lost export ….. I can live with that. 😁

But that was just downstairs. Upstairs was HOT.

Effician

Managed to keep our downstairs lounge/diner kitchen at 25c daytime temps & comfortable with a little air flow while it's been 33-34.5c peak outside , upstairs has been warmer at high 20's & the loft into mid to high 30's. As soon as outside temps drop in the evening we can get the bedrooms down to low 20's

Cost to achieve this has worked out at under £8 for reflective sheet & a daily use of around 1kWh for pillar fans ( more usually used in winter here). The trick is deal with the cause not the symptoms , obviously not as sexy as a/c but a lot less wasteful.

NedS

I had not considered, but buying a few sheets of foil backed insulation board (celotex) which is reflective and easy to cut to size, could be cut and wedged into window (and door) reveals to reflect the sun/heat on very hot days. Costs a lot less an an AC unit and zero running costs. Can be stored in garage between heat waves.

I may try that for my home office window, which easily gets up to 30C in summer. I think I have half a sheet somewhere which may just be big enough to fit.

FreeBear

Just been opening a window front & back and have a small fan to circulate air. Outdoor peaked at just under 34°C around 17:00 yesterday. This corresponded with a peak of ~33°C upstairs and ~28°C down. I went to the supermarket around that time and lingered in the chilled & frozen food isles for a while 😋