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Hi
Has anyone got any experience of these. I especially need to know how noisy they are from practical experience, not from Db figures which I don't understand. Also how reliable?
It will most likely be an 8KW model to run just the UFH only which is set at around 35 C.
They are cheap, maybe too cheap?
Any help much appreciated.
Many Thanks
 

oz-plumber

Esteemed
Plumber
Post the specs of the unit and a rough figure or % of how much cheaper they are from well known brands.
What is the warranty of the unit?
 
OP
P

PCW

Post the specs of the unit and a rough figure or % of how much cheaper they are from well known brands.
What is the warranty of the unit?
Thanks for replying, Looking on line they are a lot lot cheaper. Most likely made in China so dont expect a lot and warranty probably not worth the paper it's on. Main thing I need to know is how noisy are they? Thats always been a problem with ASHPs . So any user feedback would be appreciated.
 

Brambles

Advent Win
The Dream range for dehumidifying swimming pools are (I think) fairly good. The majority of the kit is installed inside. Sourcing spare parts is an issue - the importer Better Bargains or some such name is not very responsive.

The single phase air to water range is a bit flimsy - if you see one next to an Aquarea the difference is quite dramatic - but then so is the price.

With respect to noise, they are all very similar - if you want to minimise the “drone type noise” floor mount the external unit on rubber feet bolted into a concrete slab that is not adjoining the property. Wall mounted units sometimes generate vibration within the wall cavity.

As always with Air Source heat pumps see one in operation before you buy - A lot of my potential customers change their mind once they have seen the size of the unit (both inside the house and outside) and heard the noise.

With the latter it is often consideration for the impact of noise on neighbours that is a concern.

When you look at the design, consider using a buffer tank - it will probably increase the COP and make the installation more effective during sub -5 degree temperature spells.
 
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OP
P

PCW

The Dream range for dehumidifying swimming pools are (I think) fairly good. The majority of the kit is installed inside. Sourcing spare parts is an issue - the importer Better Bargains or some such name is not very responsive.

The single phase air to water range is a bit flimsy - if you see one next to an Aquarea the difference is quite dramatic - but then so is the price.

With respect to noise, they are all very similar - if you want to minimise the “drone type noise” floor mount the external unit on rubber feet bolted into a concrete slab that is not adjoining the property. Wall mounted units sometimes generate vibration within the wall cavity.

As always with Air Source heat pumps see one in operation before you buy - A lot of my potential customers change their mind once they have seen the size of the unit (both inside the house and outside) and heard the noise.

With the latter it is often consideration for the impact of noise on neighbours that is a concern.

When you look at the design, consider using a buffer tank - it will probably increase the COP and make the installation more effective during sub -5 degree temperature spells.
Excellent, Many thanks for the reply and taking the time.
It will be going into the bottom of a 350 litre vented thermal store. Plan is to have it running 15+ hours a day so I want to size it for that, finger in the air guess really given the kind of crazy weather we get now. 8KW should keep it busy and on really cold days can be topped up with Imerssion heater. With a COP of around 4 that will cost max £3 on a cold day most often a lot less at anything over 8/9 degrees outside. It's a big house with 6 UFH zones and approx 700 meters of UFH pipe. The house is in the countryside so no neigbours, the problem is my partner has convinced herself they are noisy, Plan B will be install away from the house and pipe it back, added expense and complication though so not prefferred.
 

Brambles

Advent Win
A couple of points:

700m of underfloor heating pipe for living space (@175mm spacing) is around 120m2 or 6kw of air source.

If you can go to ground source - it is nearly silent - you would need a 5kw heat pump and around 55m of “slinky pipe” externally buried at around 1.5m deep - depending on the ground type - it may need to be a little deeper, rarely more than 2m.

From a sizing perspective ( particularly air source) oversizing causes two problems:

The floor area will heat up quickly - using a lot of power, driving down the COP - once at set temperature, it may have difficultly holding it, without a lot of relatively short off / on cycles.

In really cold weather if the cycles (on / off) are too short, the pump probably won’t defrost properly - leading to progressively reduced performance - this is more likely in really cold weather when the defrost times are longer.

The key to a heat pump for long life and low operating costs is for it to be sized to operate for long periods at a low output. Every time the pump switches off, upon restart it will ramp up to full power. Sometimes an inverter controlled variable speed pump is a preferable solution, nut that is dependent upon the system design - summer hot water demand is an influencer in that respect.

In an earlier post, I cited Dream as being a decent option for a swimming pool - that is because they are fixed speed, virtually always on and you have an enormous heat dump to mask any design inadequacies. If they fail, it is not such a big deal if there is a lengthy wait for parts ( as once happened to me with a customer).

If in any doubt, get a local specialist to design the system for you. You will get a better result and probably save the cost of the design in reduced electricity consumption over the first winter.
 
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OP
P

PCW

A couple of points:

700m of underfloor heating pipe for living space (@175mm spacing) is around 120m2 or 6kw of air source.

If you can go to ground source - it is nearly silent - you would need a 5kw heat pump and around 55m of “slinky pipe” externally buried at around 1.5m deep - depending on the ground type - it may need to be a little deeper, rarely more than 2m.

From a sizing perspective ( particularly air source) oversizing causes two problems:

The floor area will heat up quickly - using a lot of power, driving down the COP - once at set temperature, it may have difficultly holding it, without a lot of relatively short off / on cycles.

In really cold weather if the cycles (on / off) are too short, the pump probably won’t defrost properly - leading to progressively reduced performance - this is more likely in really cold weather when the defrost times are longer.

The key to a heat pump for long life and low operating costs is for it to be sized to operate for long periods at a low output. Every time the pump switches off, upon restart it will ramp up to full power. Sometimes an inverter controlled variable speed pump is a preferable solution, nut that is dependent upon the system design - summer hot water demand is an influencer in that respect.

In an earlier post, I cited Dream as being a decent option for a swimming pool - that is because they are fixed speed, virtually always on and you have an enormous heat dump to mask any design inadequacies. If they fail, it is not such a big deal if there is a lengthy wait for parts ( as once happened to me with a customer).

If in any doubt, get a local specialist to design the system for you. You will get a better result and probably save the cost of the design in reduced electricity consumption over the first winter.
Clearly you know heat pumps, many thanks for your comments.
It is at 150mm centres, interesting rule of thumb calculation you did for KW requirement.
I would like ground source but too much work, this has been a renovation that has long overextended so need to be finished. I wish we had a stream nearby, that would be perfect.
UFH does all the tiled areas, hall etc, there are radiators in the bedrooms so I'm looking to have something that gives a residual heat and can top up with radiators if required.
You say to run at low loads, I thought better to have it at max design load?. I would like this running at least 15 hours a day.
You say Dream are a fixed speed, I guess that also accounts for why they are cheaper so maybe it's better if I get a slightly bigger one? I'd value your opinion there as it looks like you have experience with these "Dream" Heat Pumps. They say max outlet temp is 60 degrees. Seems high to me, guessing that must be under absolute ideal conditions. I was going to be happy with 40 degrees as UFH is set at 35 degrees anyway.
I'm not concerned about summer, that requirement will be by solar collectors mainly with some PV panels back up into the Immersions heaters.
Ultimately the PV panels. plus a wind turbine into batteries will run the Heat Pump also so when that happens it will run 24/7 through winter only then shut down for the summer.
Once again many thanks for your comments, very much appreciated.
 

Brambles

Advent Win
The most efficient way if operating an air source heat pump is in “unconstrained” operation - then direct the heat to where it is needed. The pump runs continuously at or near full capacity and defrosts as and when. That is how you would configure a system in a public / commercial area. In a domestic environment that is not generally realistic unless you have s large heat dump ( a decent size thermal store, pool et al).

So to replicate this in “constrained operation” the heat pump needs to thermally sized to match the installation and expected outside temperatures. This is normally achieved by correctly sizing the installation ( radiators and ufh thermal demand - match this as closley as possible to a heat pump and balancing the output with a suitably sized thermal store. The thermal store size is absolutely key to getting the system to perform. You have very little leeway with the UFH flow temperatures ( it has to match the installation type) - too cool it is useless and too hot, it is both uncomfortable and will probably over time damage the floor coverings / furniture et al. For tiled screed, I would not go much above a 45 degree flow temperature.

The second form of control is to use a heat pump with an inverter - so the compressor is in effect a variable speed drive. These are very effective (and efficient) in areas where you anticipate reasonable periods of sub zero external temperatures and /or you are using the system with comfort cooling chillers in the summer. However, they are not too good if you are using the system for hot water production in the summer.

So, in summary, if you oversize in a domestic environment, it will only run on an intermittent basis (and that may cause ongoing operational issues ) if you try to run it for longer periods you have to be able to use the heat.

My recommendation would be a fixed speed pump sized to match your system with a decent ( 600litre) thermal store. Some summer use is desirable, heat pumps generally don’t like being static for long periods.

Try not to compare these systems with gas or oil ( where oversizing is often eliminated either by the boiler modulating or the in the case of oil the output being reduced) one kW of an over sized air source heat pump is a lot of heat to disperse.
 

quality

Plumber
Gas Engineer
I agree with the not over sizing and comparing gas or oil. Heat pump air or any other source is the future. Brambels makes some good points there
 
OP
P

PCW

Some good comments, thanks again.
I have a 350 litre Thermal Store and can always top up with a wood burning back boiler and two immersion heaters if it gets very cold which is rare these days. We are in Gloucester.
The Dream units are fixed speed so undersizing it slightly I think would be better so it runs longer. Total house load is 18kw excl DHW I worked out. That's heating every room to standard temperatures. Reality is some will be off and there is only two of us so DHW requirements is minimal and my partner doesn't like it too hot anyway. It will need to run a few radiators too so I think I'll go for a 10kw.
Good point re summer use, I'll do that.
Have you got experience with these units, are they reliable?
Thanks again for your comments.
 

Brambles

Advent Win
That is far too large a heat pump for your loading.

I would advise you to have a proper design undertaken to properly determine the required pump size, COP and Seasonal Adjusted Factors before committing.

With respect to Dream, I have used them in pools for heating the pool and dehumidifying the atmosphere. They are ok. I have not used them as a domestic heat pump - the parts back up ( lead times) is not at a level that I would deem acceptable.
 
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OP
P

PCW

My gut feeling was to go for an 8kw and you suggested a 6kw. Since they dont do a 6 I've decided to take your advice and my feeling and oted for an 8kw which is being deliverred today.
If it turns out too small I can allways get a 5kw machine to run in parrallel and cut it when the bigger machine is struggling, if it's too big I'll turn on a few extra rads.
Apparantly the return stat is set at 58 degrees so will cutout then. I think that is too high for any decent effeciency on cold days so will lower it and experiment. I really only want this running UFH at 35 so have plenty to play with.
I'll post the outcome later.
Thanks again for all your comments, very much apreciated.
 
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Brambles

Advent Win
Good luck. If you are installing it yourself run it initially will all the external valves fully open and the external thermostatic controls disabled. IE. it is operating in an unrestricted mode. Leave it for a week (or longer ) to settle down and see what the performance is like.

Thereafter, introduce the minimum number of controls needed.

The logic behind this is that air source heat pumps need high flow rates - which UFH systems are really good at providing. If the flow is too restricted they will cut out - you don’t want that behaviour confusing the situation whilst you set up the system.

Even a motorised valve opening too slowly can cause an air source machine to trip.
 
OP
P

PCW

Well its been running nearly a month with the compressor on almost non stop. My calculations seem to have been OK as when it is 7 degrees or more outside it heats the whole house and the thermal store using around 1.6/1.8 kw from a 3 pin plug. (haven't wired it in properly yet). Generally it averages about 30kw a day which I measure through a SONOFF POW. Turns out I think it is more noisy than Partner does, it's a bit like the sound of a boiler exhaust and a wall silences a lot of the noise when out of direct sight.

When outside drops to 4 and below it starts struggling to keep up so I light the wood burner with back boiler which adds another 5 or 6kw to the thermal store tank. Nothing happens quickly though as normal with UFH so you have to plan a bit. One day the whole fin assembly frosted up so I had to reset the auto defrost to cut in at -5 instead of -13 and it's been OK since.
I'll keep it as is for this winter and test a bit more but at the moment considering getting another unit to work in parallel for very cold days.

Quality seems OK and I've had no problems...yet? so with two I have a standby in case needed. Apparently spares are held in the UK, hopefully I wont need to find out anytime soon.

I'm getting some evacuated tubes being delivered this week and will be building a solar thermal system shortly for more heat input to the tank during sunny winter days and DHW in the summer.
 
Hi PCW
I've been following this thread and your posts, and am wondering how the dream heat pump is working out for you,
6 months on? I have an electrical back round and have been considering DIY installing an air to water heat pump for a while now, in parallel with the oil fired system that I currently use. I'm hoping this will cut down on fuel bills & CO2 emissions. (Ironically Kerosene has dropped in price recently)
I'm planning to keep the oil fired burner as a back up, and to give me more flexibility during cold spells.
I've noticed your central heating system and load seem similar to mine, with approx 700 meters of UFH pipe in the main living area on the ground floor, (on 24/7 Sept to April) and radiators in the bedrooms, mostly upstairs, which are only ever turned on occasionally when it gets really cold. (Heat rises). Hot water is heated indirectly and stored in a180 litre cyclinder with an electrical immersion heater in summer. Is a DHW tank what you mean when you talk about a thermal store?
Anyway, problem is, good quality Heat pumps here in Ireland are extremely expensive, especially with certified installation to get the current government grant. Sums just don't add up at the moment and it could take 10 years or more, if ever, to get the costs back and then it would probably need to be replaced at that stage with a new one.
Currently, I can get an 8kw Dream heat pump like yours sent over from UK for £1250 inc. (Shipping 20% of cost)
That is why I would really appreciate your thoughts and advice to see how it has worked out for you?
Thanks
DJ
 
Always a bit wary about ASHP performance in cold weather as most are tabled at 7C. Had a commercial installation with 70kW of load however when I queried the performance at design conditions (-4C outside) the manufacturer bumped their ASHP unit up to 100kW which screwed up the spare capacity from the supply transformer changeover which was being done at the same time. GSHP is preferable if you can go for it as conditions are more stable.
 
Thanks for your input Sparkgap.
I'm wary myself about ASHP. That's why I'm enquiring. Considered GSHP 15 years ago when I was building my house, not sure our ground is suitable and couldn't justify the cost at the time. I feel retrofitting at this stage would be too disruptive, with even more added cost. Then there is still the GSHP system brand to consider.
I see Dream do those as well.
Just needed to know how PCW is getting on with his Dream ASHP? As I say, can't justify the cost of more expensive, established brands at this time, as not sure if I will ever earn the capital cost back.
If you're out there PCW, or anybody else, I'd appreciate your thoughts.
Thanks
DJ
 
OP
P

PCW

Thanks for your input Sparkgap.
I'm wary myself about ASHP. That's why I'm enquiring. Considered GSHP 15 years ago when I was building my house, not sure our ground is suitable and couldn't justify the cost at the time. I feel retrofitting at this stage would be too disruptive, with even more added cost. Then there is still the GSHP system brand to consider.
I see Dream do those as well.
Just needed to know how PCW is getting on with his Dream ASHP? As I say, can't justify the cost of more expensive, established brands at this time, as not sure if I will ever earn the capital cost back.
If you're out there PCW, or anybody else, I'd appreciate your thoughts.
Thanks
DJ
Hi
Just seen this so apologies haven't replied. Before I do, are you sorted now or would you still like my penny worth?
 
Hi
Just seen this so apologies haven't replied. Before I do, are you sorted now or would you still like my penny worth?
Hi PCW
Been sitting on it for now as not sure about it. So haven't done anything yet.
But really appreciate your penny's worth all the same?
Just a how its working for you, if you have seen any fuel savings and if you have had any problems 6 months on?
Thanks
DJ
 
OP
P

PCW

Hi PCW
Been sitting on it for now as not sure about it. So haven't done anything yet.
But really appreciate your penny's worth all the same?
Just a how its working for you, if you have seen any fuel savings and if you have had any problems 6 months on?
Thanks
DJ
Hi DJ
Will do. give me a couple of days maybe weekend and I'll reply
 
OP
P

PCW

Hi DJ
Will do. give me a couple of days maybe weekend and I'll reply
Short answer is I am very happy with it.

I wrote most of my experience in an earlier post and still have the same view.

There is a lot on the net about inverter pumps vs single speed pumps. A lot favour inverter pumps but they cost a fortune and in my opinion have a lot more things that can go wrong. Think about how long a single speed fridge compressor runs, starting and stopping for years without problems

My view is get a fixed speed heat pump and as big a buffer tank (DHW Tank, Thermal store) as you can get. Run the UFH from that and have the Heat Pump start/stop from the tank temp about 10 degrees apart. That will stop any short cycling.

Mine is connected so the hot return to the 350 litre tank is about 250 mm off the bottom and flow to the Heat pump was about 150mm directly below that (tank is 2000mm). I thought that was short circuiting, so I changed it to come off the return from the UFH, which is at the opposite side about 150mm from the bottom. So now the cold to the Heat pump is about as cold as it can get which helps efficiency. When the UFH starts shutting down the flow comes back from the tank until the tank heats up and the heat pump shuts down. So start/stop is greatly reduced.

During the colder weather <5 degrees, it never stopped running, it still heated the tank up, be it all more slowly.

It gets the tank up to about 50 degrees which is fine for showers but needs an hour with the immersion heater on for a decent bath….we’ve got a big bath…

I haven’t got the solar system working yet so can’t comment on that as a heat input to the tank.

I chose an 8kw in the end to slightly undersize the system which works OK but 10kw might have been a little better, nevertheless the woodburner back boiler helps when it gets colder. I am most likely going to get another 8kw and run it in parallel, that way when it gets colder it can assist and I will have a standby unit in case one fails.

I think these dream heat pumps are OK but as Brambles said earlier the spares back up is appalling. I needed some spares… something I did, not because it failed (why do we sometimes do stupid things doh :-/ ) but had to wait far too long and they are the only supplier and don’t pick up the phone so very frustrating.

That said when they are running they are very good, I left the heating on 24/7 setting back the UFH at night by a couple of degrees only and it used about 30kw a day. CoP I haven’t work out but even when outside temp was about 7 degrees the temp across the pump was 8 degrees on one occasion so was impressed by that.

You cant beat a nice big Thermal store in my opinion. Connect a heat pump at the bottom for base load, then you can get heat from solar, boiler, immersion heat with iboost or wood burner all adding to a big pot of heat to do what you like with. Also mine is vented, I don’t like unvented cylinders, like having a big bomb in your house and they need testing every year, what’s the point?

There’s a lot of comment about heat pumps are only effective in well insulated houses. Because of the lower temp they are slower to bring the temp up so there is an element of truth in that but at the end of the day a heat pump gives heat into the house like any heat source. If the house is getting cold then you need to put more KW in, that hasn’t changed so get a bigger heat pump. Mine is an older house and this is the reason why I left mine on 24/7. However you do need larger rads and definitely works better with a well zoned UFH system.

Incidentally flow to the heating system is also at the bottom about 250mm up so takes full advantage of the Heat pump and leaves the rest of the tank to warm up.

Happy to send pics if anyone wants.
 

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