UPDATED: Air Source Heat Pumps/Air Con - Full Info & Guide, is it cheaper to run than mains gas?

marcus_h

inasnum wrote: »

Not the case in my house - works a treat!
It does introduce cooler air and yes you'll have to heat that but I've found unless its freezing outside you don't notice a drastic difference.
I tried dehumidifiers and unless we were drying clothes it didn't get much moisture out the air. The drimaster is far superior!
We also have an bathroom extractor.
Besides all that fresh air is good, and its definitely better in winter drawing it from the loft (which is slightly warmer) than opening up windows!

Is the Drimaster a Mechanical Ventilation Heat Recovery system? And how powerful is the heater you can add to it?

matelodave

No it's not a heat recovery system it's just a fan unit which draws air from the loft via filters and pushes it into the house through a diffuser - have a look at their website to see what it looks like and specs for the heater etc

richardc1983

marcus_h wrote: »

Is the Drimaster a Mechanical Ventilation Heat Recovery system? And how powerful is the heater you can add to it?

No it's a PIV - positive input ventilation. The hearer is 500w and just tempers the incoming air from cold to cool it does not act like a fan
heater would.

See here for an overview of the system that marmitemayhem on the forum fitted... http://www.drimaster-piv-condensation-system.co.uk

Lots of info covered and pics of the install etc...

Robwiz

A Drimaster does the same thing as opening a window. It allows outside air into the house. Because the outside air is colder it can't hold as much water vapour so introducing fresh air will reduce the relative humidity of the air inside.

Before installing a Drimaster, as an experiment try opening all the windows in the home and see how quickly any condensation disappears.

pd001

Robwiz wrote: »

A Drimaster does the same thing as opening a window. It allows outside air into the house. Because the outside air is colder it can't hold as much water vapour so introducing fresh air will reduce the relative humidity of the air inside.

Before installing a Drimaster, as an experiment try opening all the windows in the home and see how quickly any condensation disappears.

I like that explanation, simple and dead easy to understand. Opening the windows. therefore venting the property, does indeed clear condensation on windows.
However, its a fact that in winter, a house becomes cold very quickly with the windows open, even slightly ajar.

I have another thread running which is about condensation and damp.
When certain other issues are sorted out in the house on that thread, then my daughter may well consider installing a Drimaster unit in the loft.

richardc1983

Yes correct but opening windows in winter does make a house very cold as you have said as you have air coming in at many diff points. The Drimaster vents in one central point on the landing which in turn mixes with warmer air and circulates the fresh air throughout the house rather than the cold air (via opened windows)going straight into the room from outside.

pd001

richardc1983 wrote: »

Yes correct but opening windows in winter does make a house very cold as you have said as you have air coming in at many diff points. The Drimaster vents in one central point on the landing which in turn mixes with warmer air and circulates the fresh air throughout the house rather than the cold air (via opened windows)going straight into the room from outside.

Hello Richard,
you are contributing to my other thread and I thank you for your helpful comments over there.

In general terms, I understand the way the Drimaster system should work, and it if it does work, it seems a pretty cost effective way of getting fresh air into a house that hopefully, a tenant would have no control over. By that I mean that with all the controls, and indeed the unit itself in the loft, they couldn't turn it off at will.

My daughter is eventually prepared to look at the Drimaster system further, but because she is proposing to take other remedial steps, ie installing fans, loft insulation, etc, then its only fair that these measure are evaluated over what is left of this winter and the coming spring and summer.

However I started the other thread thinking that the Drimaster system would be a pretty good solution to the problems in her rental property.
It still maybe a good solution, after the other work is completed?

richardc1983

Yeah see how u get on after the other work is completed. extractor fans will help there's no doubt about that

richardc1983

matelodave wrote: »

Most heatpumps are specified to work at 35 degrees and I read somewhere that every degree above that increases the cost of running it by about 2,5% so the lower the temp you can run the system the better. A 50 degree flow temperature could therefore cost 37.5% more than 35 degrees, just by reducing it by 5 degrees could reduce your consumption by 12.5%


It shouldn't be too hard to get operating, installation and commissioning instructions from the internet which would help with tweaking it. You can also then see if they are running the system on the edge of the booster heater, like wise, at what temperature are they keep the hot tank. The lower the temp the better otherwise the immersion might be kicking in. Check the temperatures where the heaters cut in and try to run the system below that.


I run my system with weather compensation which means that the unit only winds up it's temperature when it cold and reduces it when it's warmer. If you can optimise your flow temperature to match the house heat loss you should be able to reduce the running costs a bit. If you need 50 degrees when it's zero outside you should be able to get away with 40 degrees when it's plus 10.


Do some heatloss calculations for each room and check the radiator sizing for the flow temperatures that you are using and add them together to make sure that the unit is big enough to heat the place without flogging its heart out.
It took me a couple of winters to tweak mine but it's now pretty well optimised - we've used 500kwh less this December than last and 600kwh less this January compared with last years. That's a saving of over £120 over the same period last year

My partners mum has a Samsung ehs heat pump and it was set for a max flow temp of 50c under compensation. She's had a bill for 400 for two months. Temp is at 20c during timed on and night set back to 19c it runs for about 8 hours a day during the timed on periods. We're getting no where it's the company that installed it they have been out and recommisioned it made a right hash of it, there was zero pressure in the system and the radiators were cold half of them because they haven't bled them of filled the system properly. All rads had their balancing valves fully open so some rads further away were stone cold, I've balanced the system properly and we're getting a 10c drop between the send and return flow temps.

I sorted the above yesterday as I decided enough was enough. Her husband is in his last year of terminal cancer and she is sat in a coat in the house, the stupid install company are useless and don't care. Even though it's never worked properly in the 2 years it's been in with extortionate energy bills. I've adjusted the max flow temp to 45c and the house is still toasty. Theres a +-5c option where the user can increase or decrease the flow temp. I've turned it down to -5c so flow temp is now 40c and rads still nice and warm. This morning the unit has used £1.04 since midnight rather than the £3.50 it would have used. She's a fan convector in the kitchen which also helps to put heat into the house quite efficiently. Is there anything else we can do to optimise this system, I am thinking of trying max flow temp at 40c if house is warm enough meaning at -5c setting flow temp will be about 35c. It is tweaking it now and as I work in this area in HVAC I have a full understanding. Hot water cylinder temp is 48c and the system is set to use no immersions at all apart from the weekly boost to 60c for disinfection purposes.

Heat curve is set at outside temp of -2c as per Samsungs suggestion but it also suggested setting it for -6c for Scotland? Any reason for this? Surely -6c would be better as your giving it more scope to adjust down and be more efficient.

Regards
Richard

[Deleted User]

richardc1983 wrote: »

My partners mum has a Samsung ehs heat pump and it was set for a max flow temp of 50c under compensation. She's had a bill for 400 for two months. Temp is at 20c during timed on and night set back to 19c it runs for about 8 hours a day during the timed on periods. We're getting no where it's the company that installed it they have been out and recommisioned it made a right hash of it, there was zero pressure in the system and the radiators were cold half of them because they haven't bled them of filled the system properly. All rads had their balancing valves fully open so some rads further away were stone cold, I've balanced the system properly and we're getting a 10c drop between the send and return flow temps.

I sorted the above yesterday as I decided enough was enough. Her husband is in his last year of terminal cancer and she is sat in a coat in the house, the stupid install company are useless and don't care. Even though it's never worked properly in the 2 years it's been in with extortionate energy bills. I've adjusted the max flow temp to 45c and the house is still toasty. Theres a +-5c option where the user can increase or decrease the flow temp. I've turned it down to -5c so flow temp is now 40c and rads still nice and warm. This morning the unit has used £1.04 since midnight rather than the £3.50 it would have used. She's a fan convector in the kitchen which also helps to put heat into the house quite efficiently. Is there anything else we can do to optimise this system, I am thinking of trying max flow temp at 40c if house is warm enough meaning at -5c setting flow temp will be about 35c. It is tweaking it now and as I work in this area in HVAC I have a full understanding. Hot water cylinder temp is 48c and the system is set to use no immersions at all apart from the weekly boost to 60c for disinfection purposes.

Heat curve is set at outside temp of -2c as per Samsungs suggestion but it also suggested setting it for -6c for Scotland? Any reason for this? Surely -6c would be better as your giving it more scope to adjust down and be more efficient.

Regards
Richard

Hi Richard,


I don't have any flow temp figures to hand right now but can offer this information.


Weekdays: 05:30am to 08:30am 21c - I get up early ;-)
Weekdays: 5:00pm to 09:30pm 21c
Set back to 17c outwith


Weekends: 06:30am to 9:30pm 21c
Set back to 17c outwith


DHW set to 50c however...as the solar immersion generally boosts way higher than this the there is no need for e.g. weekly boost to 60c for disinfection purposes.


In the real world... with the wife working part time the system is usually on all day on two of the weekdays and of course on all day on school hols :-( Not bothered as long as its sunny :-)

Running costs... 5th December 2014 to 7th January 2015 ~£144 with solar panels covered in snow for some of that time.

Cheers


Colin