Impact of installing Air Conditioning in Flat on Energy Rating

saskay

Hello, my flat gets very hot during summer, living room has a large glass panel and it can reach upwards of 28 to 30 degrees Celsius and upto 25-27 degrees elsewhere in the flat. The problem is my flat is East-West oriented and the living room gets direct sunlight from about 2pm to 8pm during summers. My poor dog becomes miserable during the summer months. I already have floor fans and a Delonghi portable A/c but that's only good for a bedroom and it is not run as efficiently since putting the air outlet pipe through the half open window doesn't seem to be very efficient.

So, I'm contemplating installing a central A/C so all rooms get a A/c unit. My balcony has sufficient space to install the external unit and the landlord will consider A/c installation requests. Now, coming to my questions:

1. I may be in my flat for another 1-2 years before I sell up or rent it out, I was wondering what impact having a central A/c system have on the Energy Rating of the flat - currently it is rated "B" (apartment built in 2016). My concern is if I choose to rent out, then I heard that landlords need to make sure the rental properties meet a minimum energy efficiency rating (not sure if my installing the A/c) will make it hard to rent out or (even sell).
2. Does anyone have any idea how much it costs to a. install & b. run a central a/c system for a 3-bed apartment (900 sq. foot)?  As I said, my apartment is just over 6 years old, and apart from 3 months in the summer, there wouldn't be any need to run the A/c. During winters, I only need to run the heating every now and then. In that respect it is pretty well insulated.
3. Are there any Eco-friendly things I could do to reduce the amount of sun coming to my flat? Are there any type of climbing plants that I could use to provide shade over the window to block some of the sunlight? Any other suggestions welcome.
   

QrizB

On your point 2, @danrv paid about £7k last year to have a multi split system fitted to his 3-bed semi and has a thread here. His system was fitted as an alternative to storage heaters for heating but it also provides AC. If you're happy with a multi split then you'll be looking at a similar cost. (US-style "central air" will be much more expensive and disruptive as it involves blown air ductwork.)

pochase

The AC in the thread mentioned by @QrizB is a 10KW. So just using it for the time from 2pm to 8pm which seems to be the worst would be 60KWh or £16.80 per day. That is over 500£ per month.

Yes you will not need to run it every day, but it is also likely you will have to run it more than the 6 hours on hot days. 

We were looking into getting one ourselves last year, but with the new energy prices we have stopped the plan as it will be jus tto expensive.

BUFF

saskay said:

1. Are there any Eco-friendly things I could do to reduce the amount of sun coming to my flat? Are there any type of climbing plants that I could use to provide shade over the window to block some of the sunlight? Any other suggestions welcome.
   

Do you already have blinds ?

Ally_E.

Your best bet is to look at making your portable aircon as efficient as possible. There are covers for windows to reduce hot air blowing in, if you're using the aircon without anything to stop the hot air blowing in, of course it's not working properly and is using up energy like crazy. Here's the type of covering on velcro that we use during the summer with our portable 9000BTU aircon https://www.amazon.co.uk/Universal-Portable-Conditioner-158Inch-Exchange/dp/B099Z2NJ9B/ref=sr_1_3?crid=CKOVXLQV2L99&keywords=aircon+window&qid=1651230112&sprefix=air+con+window,aps,60&sr=8-3 It's a bit tidious to fit it making sure there are no gaps for warm air to come through, but once set up you can leave it for the whole of the summer and use the zip to open window to air out. 

I had a look at our energy consumption and we used around 15kw/h a day when using the unit with a missing plug for condensation, which mean the water was draining out and aircon was mostly working on compressor. When we ordered the missing plug from manufacturer, the energy use went down to 6kw/h a day. Our bedroom would also warm up to 28-32 degrees and was south facing. 

And like someone already mentioned above make sure you have blinds, we had 2 sets. Blackout blind and a heavy venetian blinds, plus curtains. All of them were closed at all times during the heatwaves to reduce the room heating up. 

ATaleOfTwoWaffles

Similar to blinds, perhaps shutters. External shutters would cut down the light reaching and coming through the window. Might not be easy to fit/allowed depending on the height and lease conditions of the flat. Internal blinds / shutters definitely easier.

MWT

pochase said:

The AC in the thread mentioned by @QrizB is a 10KW. So just using it for the time from 2pm to 8pm which seems to be the worst would be 60KWh or £16.80 per day. That is over 500£ per month.

They don't just run full blast from the moment you turn on until you turn off, it is highly unlikely you'd be using 10kW for the entire period.

Check the end of that thread for more realistic actual usage numbers...

markin

Unless your portable A/c unit has 2 pipes, you are either drawing in hot air from the rest of the house at 30c or from the window, hopefully outside air is cooler than the 28c in the evening, probably not in the last heat wave. Just a single air unit could possibly cool the entire flat as its far more efficient when you aren't bringing in more hot air, and more powerful than most portables.

You could also have some windows professionally tinted or the bottom half if its a patio door, You don't want it too dark in winter.

Phlik

ATaleOfTwoWaffles said:

Similar to blinds, perhaps shutters. External shutters would cut down the light reaching and coming through the window. Might not be easy to fit/allowed depending on the height and lease conditions of the flat. Internal blinds / shutters definitely easier.

To the op, external shutters will work very well but if you can't fit them it might be possible to have a reflective film applied to the outsides of the glass.

Personally I'd exhaust all options for stopping the heat getting in first rather than looking at ways to cool it back down.

saskay

BUFF said:

saskay said:

1. Are there any Eco-friendly things I could do to reduce the amount of sun coming to my flat? Are there any type of climbing plants that I could use to provide shade over the window to block some of the sunlight? Any other suggestions welcome.
   

Do you already have blinds ?

No, only black out curtains.

saskay

Phlik said:

ATaleOfTwoWaffles said:

Similar to blinds, perhaps shutters. External shutters would cut down the light reaching and coming through the window. Might not be easy to fit/allowed depending on the height and lease conditions of the flat. Internal blinds / shutters definitely easier.

To the op, external shutters will work very well but if you can't fit them it might be possible to have a reflective film applied to the outsides of the glass.

Personally I'd exhaust all options for stopping the heat getting in first rather than looking at ways to cool it back down.

Thanks - I'm also considering something like this: https://www.manomano.co.uk/p/manual-retractable-awning-200-cm-cream-10989857?model_id=10960256