Air Source Heat Pumps

greendwarf

1962cal wrote: »

Hi.



I'm new to this forum. We had an 14.4Kw ecodan fitted in the summer. We have noticed over the past fortnight that our electricity usage has gone up to about 75 units a day! We run the system all the time to try and keep the house to a reasonable temperature, 15c at night and 18c during the day. Is anyone else experiencing this problem with their ASHP or is this just a fact of life? We moved from a life expired GCH system to ASHP with the existing rads.

The house is fully insulated, it had to be to get the grant! We pretty much turn most things off to save energy costs.

Any advice?

Carol

Can I ask what you mean by fully insulated?

1962cal

Hi.

What I mean by fully insulated is, 270mm of Loft Insulation, Cavity wall insulation and double glazing. We had to have all these things in order to qualify for the grant.

The ASHP is maintaining the temperature and you have confirmed my expectations that it is working to spec, however at 14p a unit (I'm with SE) it is costing £10.50 per day to run which is quite a lot of money.

Oh well.

Carol.

1962cal

richardc1983 wrote: »

Yes thats correct in these temps it will be running and working harder you have to understand though how much your saving through summer on hot water and also the rest of winter when its milder... its normal.

Is it maintaining temperatures for you though?

Does the Ecodan have electrical back up heaters? maybe these are coming on? What do you have the flow temperature set at, you should only have it set at about 50-55C otherwise the heaters come on.

We don't have any back up heaters. I have set the flow temp to 50c for heating and 55c for the hot water. We do have a 'real fire' so that has been used over the past couple of weeks.

I suppose it is extremely cold at the moment. I am keeping readings so I will see how it averages out over the year.

Carol.

Carol.

richardc1983

Are you sure there is no electrical heaters coming on to boost the water temp with it being so cold? Many system do have these as standard inside the tank etc.

eugeneg

Carol, I asked exactly the same question 10 months ago when my ASHP was new and I was paying much more than I expected. I then started logging the average temperature against usage each day. You are normal. There is a close correlation between temperature and electrical consumption, and the ASHP is at its most efficient when the outdoor temperature is between 8C and 18C in my experience. I supplemented my system with solar preheating for the summer and a log fire for the Winter.
You may be able to get a better rate on electricity though - I switched (to eon) and now pay a tad over 9p.

arty68

That's what put me off the Ecodan the system that is sold as a package doesn't have a backup heater for the heating as the cylinder is only for hot water, the HP is connected directly to the heating circuit. So your hot water can be backed up by an immersion but there's no backup for the heating.Hope this makes sence head's a bit fuzzy this morning..

1962cal

richardc1983 wrote: »

Are you sure there is no electrical heaters coming on to boost the water temp with it being so cold? Many system do have these as standard inside the tank etc.

There is an immersion backup but it's switched off at the moment. This is our first winter with the ASHP and until the temperature dropped it was saving money.

All the replies so far have been useful and welcome. It's reassured me that the system is performing as normal.

As an aside, we had some trees cut down 2 years ago and turned into logs. They are just ready to burn. So time to use the 'Real Fire' for a while.

Many thanks to all that responded.

paceinternet

I have set the flow temp to 50c for heating and 55c for the hot water.

It may not be the right time to experiment but maybe consider:
1. Remember, your heat pump will be more efficient (kw used for kw out) the lower the output temperature you ask it to make.
So if your room heating can heat the rooms using 45 degC water, it will use less electricity. Maybe it can't if it doesn't have enough surface area.

2. Same applies to your domestic hot water, but with the legionella twist.
The validity of the next statement depends on the type of hot water tank you have. If your domestic hot water is stored in a tank:
If you can't regularly heat your hot water to 60 degC, you should be daily/weekly raising the whole tank temperature to 60 using the immersion heater. If that is the case, you may not need to use 55 unless there is a quantity problem, because hot water at anything above 40 is likely to have to be mixed with cold water at the tap or shower point.
If your domestic hot water is "heated on demand" through a coil in a buffer tank, you may find it needs the heat pump to run at 55 to get an acceptable temperature at the tap, and then the legionella issue is not likely to be a problem.

Andy_WSM

Swipe wrote: »

have you still got your unit in the loft Andy? How do you go about drainage?

Isn't it funny that you should ask this question a couple of weeks ago, I say "not a problem" then suffer a "condensation flood" weeks later

I am seriously considering moving the unit to the back wall of the bungalow - outdoors, as I just can't risk the sort of mess I woke up to at 3am this morning again. I heard water trickling through the bathroom ceiling and when I got out of bed to investigate there was a flood from the bathroom to the hallway. I panicked and assumed a burst pipe somewhere so switched off the water main - but the water kept coming!

When I opened the loft hatch....ICE everywhere. The Trianco was like a giant block of ice, with a clearing where the compressor coil and fan are. There were icicles hanging off the front grill, under neath it - off the timber work that it stands on. Oh dear! Obviously the internal drain was frozen solid, as was the pipe that leads the condensate away to the guttering.

The result of opening the loft hatch was a massive flood in a very short amount of time and I could do nothing to prevent it!

This has obviously been going on for a few days - maybe a week, as the timbers, the loft insulation, the ceilings, everything are soaked (actually, soaked & frozen!).

Sure, if the unit had been outside it may still have iced up that bad (although I suspect not!) but then it defrosted itself the worst I would have suffered was a wet patio!

I now have a 3KW fan heater blowing warm air in the vicinity of last nights flood and the loft hatch open to help air things through.

Swipe

Wow, sorry to hear that Andy. If I were you I'd move it outside, that can't be good for your roof. I've also been getting condensation in the loft during this cold spell on the days that there is no wind. I plan to install more vents.