Modern CH pump saves 200 kWh per annum

Fred_Bear_2

I was shocked last year to find that my central heating pump was using more electricity than my washing machine! My pump was an ordinary Grundfos pump and used 65 watts. I have now changed it for a new Grundfos Alpha 2 which averages about 8 watts. If it was running continuously it would save 500 kWh per annum. For my system I expect it to save about 200 kWh per annum.

decsdad

Thats about £24 per year(based on 12p per kwh), how much did you pay for the upgrade ?

Cardew

I posted about these pumps some while ago.

The cheapest price I have seen is £152 with, say, another £60? to fit.

The other pumps range from £50 to £70.

When mine gives up the ghost, I will look at getting one but not until it is kaput.

Fred_Bear_2

I paid £104.47 for the Alpha 2 last December from BHL.co.uk. The Alpha 2L at £89.23 is the same except that the Alpha 2 has a digital display showing the energy consumption. I fitted it myself in 20 minutes so saved the fitting cost. Yes I could have waited till the old pump broke, but in my experience pumps last a very long time (20 years plus) and for me it makes sense not to wait that long.

mech_2

8 watts? That's impressive. Mine is 50 watts, but it's built into the boiler, so any replacement would have to fit physically. I don't think it's worth it, considering that my best estimates come to less than 100 kWh saving per year.

barrymung

The pump shouldn't be running very long, only while the CH is actually heating. If it runs for a long time then I'd question whether the house is properly insulated-probably would be more cost effective to insulate the house!

Worthwhile if replacing a broken pump though, most certainly.

Fred_Bear_2

Thanks for the replies.
On the subject of insulation, the problem is I live in an old house with solid walls. I have calculated the heat loss using a spreadsheet and find that most of the heat loss is through the walls. Having the walls insulated externally would cost many thousands, and internally there is the problem of messing up the cornice etc and making the rooms smaller.
Re the boiler: As I understand it the boiler should be sized so that it is running most of the time during the heating season. It is inefficient to have a large boiler switching on for short periods. That's why modern boilers modulate their output from say 5kW to 15kW to keep them on for the maximum time.

jonesjw

That 200kWh is not wasted -the energy will all be converted into heat either given off directly from the pump body or as kinetic energy of the water, which will be converted to heat as the water slows down.

Assuming the pump is located in a location where the heat given off is useful, your annual energy saving will be precisely zero, as you will just burn more fuel to generate that 200 kWh.
However, you may save money as I think electricity is roughly four times the price of gas.