Man of Honour
- Joined
- 21 Nov 2004
- Posts
- 46,224
And tbh you can get some really stylish units these days. Too many people, including myself, imagine those old, noisy and ineffective units you sometimes see in Spain and the like.
Split Air con
- Thread starter YoungBlood
- Start date
And tbh you can get some really stylish units these days. Too many people, including myself, imagine those old, noisy and ineffective units you sometimes see in Spain and the like.
Soldato
- Joined
- 22 Feb 2014
- Posts
- 2,779
Can't justify £4k for a ducted unit to myself to be honest let alone her, £1700 isn't too bad though. I could throw some man maths at her and get that done.
But I've looked at the"sleek" unit dimensions and they are marginally smaller than the one I have at work and that is pretty big tbh.
She doesn't see value in things like this which improve the house and quality of life, which is incredibly frustrating at times, I have to keep sneaking things in under the radar.
I'll just have to make do with the noisy portable one again in summer.
I think there is something wrong with your boiler/central heating though.
I've had the house heated to around 18c all winter and only spent on average £2.84 a day, that also includes hot water for washing up and showers.
That sounds incredibly cheap. My house is at least £8 a day in winter but insulation isn’t great apart from the loft. New boiler fitted last year too.
I don't think many people/installers put much/any effort in making central heating efficient.
I've spent a lot of time and effort doing it.
Associate
Apologies for repeating myself, but is anyone running a wall mounted (ductless) and a ducted indoor unit from a single outdoor unit (multi split) ?
Yes, 7.2kW outdoor Mitsubishi Electric, with a 4 bedroom 5kW ducted loft unit and a 3kW wall unit downstairs in the lounge. Want to get one more unit added to the conservatory and the installers said this will be fine to add to the existing outdoor unit.
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This was on a very cold day, which maybe makes a difference - the boiler was running flat out throughout that hour. Bear in mind that your £3 a day is not the boiler running constantly throughout that day.
Our average daily usage is around £4-5 in gas. But the experiment I mention was an opportunity to perform a direct comparison of cost compared to temperature change, as the house was chillier than usual that day. I was astounded by how efficient and how rapid the air-con was in heating mode. The reason it only cost 6p was because it only had to be on for about 5 minutes to achieve the temperature we wanted.
When you're used to reading energy usage for your electrics, and then you translate the cubic metre readings from your gas meter into kWh, it's obscene!
I haven't kept the piece of paper I doodled my calculations on, but working back from my remembered £2.14, that means it burned over 20kWh in that hour!
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Which day then I'll check how much I used that day or even the first hour it came on.
Your ignoring thermal mass as well with your comparison. You can't just look at initial warm up times.
While you may initially use more with gas that great hasn't all gone into the room yet it's contained within the system.
I don't doubt they are efficient but the maths just doesn't add up for me.
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I have absolutely no idea which day, it was months ago. And it makes no difference to what you're trying to compare. All you need to do is a meter reading before, and a meter reading after, an hour period when your boiler is running for the whole hour.
I'm not ignoring anything. There are several variables which contribute to that amount of energy ending up in that temperature change - but they don't change the equation for the purposes of comparison. Because to me as the user, the cost and the temperature change are the only considerations which actually matter in the end.
The one exception is that, of course, after the hour the rads continue to be warm, and therefore will continue to help the room temperature somewhat. But if they only raised the temp by a degree during the hour that they were as hot as they get, they're not (and didn't) going to make a dramatic difference as they cool.
I'm not ignoring anything. There are several variables which contribute to that amount of energy ending up in that temperature change - but they don't change the equation for the purposes of comparison. Because to me as the user, the cost and the temperature change are the only considerations which actually matter in the end.
The one exception is that, of course, after the hour the rads continue to be warm, and therefore will continue to help the room temperature somewhat. But if they only raised the temp by a degree during the hour that they were as hot as they get, they're not (and didn't) going to make a dramatic difference as they cool.
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Caporegime
Boiler gas usage is variable not static, taking a gas meter reading for an hour then extrapolating that over x number of hours use is incorrect.
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Associate
We had a 8kW Mitsubishi split unit installed at the beginning of June last year and it was the best thing we've ever done. We have indoor units in three rooms (kitchen, main bedroom and Living room), but if you have the doors open it'll cool the whole house nicely when all three are running. Performance-wise they blow the mobile units away. We used to run two upstairs and there is no comparison. During that spell last summer it was 37C outside and inside was at a steady 21C in pretty much every room. I cant imagine what it would have been like without them as this house is a new build and holds heat in very effectively. Power usage is not too bad either, around 600-700w when running. Fortunately that is not an issue now we have solar, but at around 65p/hour at current prices, its worth it for the comfort.
I've yet to try it in heating mode, however now we've got the solar panels I might give it a try and save on some gas costs too.
I've yet to try it in heating mode, however now we've got the solar panels I might give it a try and save on some gas costs too.
Associate
Any chance you could take a video of the outdoor unit in operation please? I understand that noise levels are relative, just curious to hear it
What? Who said they were doing that?
I took a reading over an hour to measure how much I had used that hour, I haven't extrapolated anything!
You are all sort of right but also sort of irrelevant. All that matters is the price differential between gas and electric and the coefficient of performance for the air to air heat pump. Electricity is 3.22 times more expensive than gas which means the air to air heat pump needs to hit a coefficient of performance of 289% assuming that your gas boiler is at most 90% efficient (very unlikely).
If a modern air to air heat pump is not hitting 289% in heating mode in the U.K., you've got a problem.
If a modern air to air heat pump is not hitting 289% in heating mode in the U.K., you've got a problem.
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Soldato
+1 for subcool here. Very good and aware of their popularity on this forum
Associate
Has anyone bothered with getting a planning permission before going ahead with their install?