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Keeping running costs low


Tramontana

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Hi - I'm not a self-builder, more a renovator, and I'm not skilled in all departments so I mostly decide what I want and pay others to do the skilled work. I bought a small 1950s house as my "forever home" so I don't have to justify capital outlay (as I'll never see it anyway); I'm more concerned about keeping future running costs as low as possible, as a hedge against a severe drop in income and/or massive rises in prices. So I started by installing solar PV, mostly for hot water via a Sunamp heat store. At some point I'll add a battery as I'm getting far more power each day than I need just for hot water, but I'll wait a bit as the prices are dropping. Next on the list is a heatpump for the central heating, replacing an ageing gas boiler.

 

The part I'm doing all myself is smart control of heating, only turning on radiators when/where they are needed, on a room by room basis via electric radiator valves driven by wifi relays. Temperature measurement is done by wifi thermometers in each room, and a Rasperry Pi computer looks after the system. Data is sent to and from my website and monitored/controlled through a mobile-friendly web app. By doing it myself I can drastically reduce the hardware cost compared to something like Hive. I've come here in case there are others working on similar ideas I can compare notes with., and also to pick up tips about other things that may be related to the overall project.

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Welcome, Welcome. 

 

Control the air in the house via airtightness and mechanical ventilation. Otherwise your house will be either too drafty or too stuffy. 

 

Then upgrade the U-Values. The cheapest energy is the energy you don't use. 

 

 

Good luck. 

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I wouldn't advise zoning your heating system too much if you plan to drive it with an ASHP... Lots of information out there about that, but Tl;dr - weather comp, ashp on 24/7, nighttime setback by 2deg...

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  • 5 months later...
On 21/04/2022 at 16:39, SteamyTea said:

Welcome.

Have you already got the Sunamp?

Hi, I posted the original note then lost the link and I've only just rediscovered it. 
Yes, I had the Sunamp installed in May and it's been working great ever since. The Thermino 150 is an excellent match to a 12-panel solar array and I've only had to top up (for about 30 minutes) once since then.

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On 21/04/2022 at 16:41, HughF said:

I wouldn't advise zoning your heating system too much if you plan to drive it with an ASHP... Lots of information out there about that, but Tl;dr - weather comp, ashp on 24/7, nighttime setback by 2deg...

The ASHP wasn't needed all summer so it only started work at the beginning of October. The automation system mostly ensures that only 1 or 2 rooms are heated at the same time, so the water heats up pretty quickly. My particular favorite is a hydronic under-plinth heater in the kitchen, which takes up no space, is almost silent and delivers heat instantaneously if the flow temp is 40 degrees or above. Having a wifi thermometer and electric radiator valve in in each room gives total control and so far hasn't shown any downsides. Right now - mid-October - my total energy input from the grid is running at around £3 per day, and we always maintain a comfortable temperture wherever we are in the house. OK, so there's only 2 of us, it's a small house and it gets a lot of solar gain but that's a figure I'm more than happy to live with.

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22 hours ago, Tramontana said:

The automation system mostly ensures that only 1 or 2 rooms are heated at the same time

I would get you stop watch out, and ensure running that regime is not giving you short cycling, your heat pump needs to running about 10mins as a minimum.  

 

Other thing to consider is internal heat loss running a couple of rooms only.  What happens is you end up running the heating in the rooms heated, hotter than you would if you heated the whole house.  That impacts the CoP so you could be cheaper more comfortable running the whole house at a low flow temp.

 

I would certainly experiment.

 

£3 doesn't sound much but that's 9kWh.  Or 30 to 45 kWh of heat depending on the CoP. With the current weather you should be getting a mid 4+ maybe 5 CoP for heating.

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