Air to Water

murphaph

air wrote: »

Suggest you stick to German forums then.

Go ahead and install your single heat source and report back please.

murphaph

air wrote: »

Or as I suggested you could put a unit in each room.
I posted the links to the system as I thought it might be useful for some people that might not have realised that heat pumps can be retrofitted relatively economically.
One wouldn't need to use it as the exclusive heat source, but with a COP of 3 one could heat the house overnight for less than 3c / kWh in Ireland on night rate which is cheaper than any other fuel source.

There wouldn't be anything economical about buying a €500 heater for each room and having multiple compressors running to heat one house, never mind the difficulty in controlling such a system. The least efficient aspect of running a heat pump is the start up current required to get the compressor motor turning (once it starts it's very efficient however) and you suggest multiplying this problem. Where would you put them anyway? Your house would look like the back of a supermarket.

murphaph

Water John wrote: »

Those would be the zoned temp for these rooms, in Ireland too. 21,23 & 18.
Yeah would be difficult from one dry source.
That's the purpose of rads or UFH.

Sadly some people still putting in these systems and only one thermostat. Defeats the whole potential.

Yeah in our house the internal walls are insulated and between floors too. Our system has a thermostat in every room but I intend on eliminating them and getting everything set up hydraulically, reducing flow to "colder" rooms at the manifolds. Those thermostatic valves and thermostats consume a decent amount of electricity and aren't really needed if the hydraulic balancing is done properly (assuming loop lengths are consistent).

air

Murphaph, your post is nonsense, it appears that you really haven't a clue what you're talking about.
First, startup current has no impact on efficiency. It's a factor for diversity, MIC and other aspects of AC infrastructure but only lasts a second or two so has no impact on overall system efficiency.
Secondly the unit I posted & pretty much all of those on the market are inverter units with no inrush current issues.
As for locating the outdoor units they can be located over 15m away, easily accommodated in a louvred enclosure outdoors.
As regards heating bathrooms to 24C ostensibly for the 10 seconds a day there's someone naked in there, quite frankly ridiculous.
As for the difficulty of control, each unit would have individual time and temperature control, better than most systems.

murphaph

If you want to install such a system, be my guest air. It's your money and comfort.

air

KCross wrote: »

air wrote: »

Or as I suggested you could put a unit in each room.
I posted the links to the system as I thought it might be useful for some people that might not have realised that heat pumps can be retrofitted relatively economically.
One wouldn't need to use it as the exclusive heat source, but with a COP of 3 one could heat the house overnight for less than 3c / kWh in Ireland on night rate which is cheaper than any other fuel source.

Running them at night wouldn't really work though, would it?

Heating the air is very different to heating a concrete slap with a HP. You don't want 23C going into the air during the night.

So,realistically, wouldn't they be running at the day rate, not nightrate?

Definitely, you'd have to run them during the day but you could still have them ticking away at a lower temperature overnight too.
Even during the day it's heat for 6c/kWh though which isn't much higher than natural gas so possibly a good option for people off the NG grid.

Water John

I would find it strange to consider dropping thermostats and actuators because of electrical use. The capital cost has been spent. The running costs must be absolutely minimal.
Maybe consider the opposite and taking out the flow meters and blanking them. They are actually a fairly significant impediment to flow.

air

Not sure what you mean? These are air to air heat pumps, set backs at night are standard.

murphaph

Water John wrote: »

I would find it strange to consider dropping thermostats and actuators because of electrical use. The capital cost has been spent. The running costs must be absolutely minimal.
Maybe consider the opposite and taking out the flow meters and blanking them. They are actually a fairly significant impediment to flow.

The capital cost was unavoidable due to the building regs here. You have to install zoned control of your heating system. Every room designed for occupation must have a room thermostat or no planning permission and no architect sign off.

I've read on several German forums that they consume a not inconsiderable amount of electricity, especially when you have 14 of them. I have read that many folks here remove them, either entirely or in all the warmer rooms, leaving room thermostats only in the bedrooms.

I'll measure what they use before I decide exactly what to do but I've so much to do that this is all going on the back burner for now.

Water John

I'd only have stats in each bedroom and any living space that had a second source of heat eg stove. Rest I would leave open.

Doorcase

Will be going with air to water now. Just wondering is the 180 L water tank of hot water plenty or should i get the 300 L integrated one. any experiences of both?

Water John

Personally would go with the 300l, 180 is very small.
Some people put in a quite large tank 1,000l up. They then run the HP at night. Use a secondary loop to heat the house from this, during the day.
You would put this in a small plant room or garage.

murphaph

Don't forget you need to heat the water up to over 60 degrees at least once a week to kill legionella bacteria. The heat pump won't be able to hit that temperature. If you are relying on an immersion heater to do it it is more expensive the bigger the tank so biggest is not always best...size the tank appropriately for your needs IMO.

Water John

The loop between tank and HP is closed.

regvw

halfforward wrote: »

FiOT wrote: »

My two pence, however much it's worth, is to think about who is supplying your heat pump as well as what heat pump you're getting.

A well - reviewed company with good customer service definitely won it for us between two similar heat pumps in the end. No point in having a fabulous product if there's nobody to come and see it if it needs to be fixed in the future!

Who did you go with? PM please
Trying to decide?

in exact same position here, would love to know who you went with PM please

regvw

Water John wrote: »

The reality for most builds is high insulation and sealed envelope. Heating bill then will actually be quite low 4/600 per year.
Also with a sealed envelope be sure to install MHRV costing about 5K. Very little operating cost.
With those low annual running costs, the diff in COP between A2W and Geothermal doesn't justify the extra capital cost.
The use of UFH or Alu Rads is a personal choice. Certainly would not bother with UFH upstairs, just alu rads.
Set Thermostats in living area to 20/21 C. Bedrooms at 18 and can drop to 16 c at night.

Water solar heating is a complete waste of money and very poor ROI. Saves about 170/year and costs 3/5K. Just think how much hot water you actually use?

hey, John just in the middle of all this now myself
I got quoted for UFH downstairs and alu rads upstairs, I was wondering why would I go with teh rads upstairs be it they are a bit cheaper, is there any other reason to put them upstairs
also supplier included a HRV, do I need one, its now specified in my BER spec

thanks
Reg

regvw

Water John wrote: »

The building and the stale air in it will not be healthy. To my mind a sealed building and HRV go together. Otherwise you will have sick building syndrome and a real headache.

If I took a simple approach ans opened the window to get some air in, would this work ?

Water John

I would go with the alu rads.

Ah stop, the day of someone being in the house to open a bit of a window are gone. It isn't because it's a warm summers day, one is looking for air change. Its the fact that the people in the house are breathing in oxygen and breathing out carbon dioxide, all the time.
Do you feel like 'opening the window tonight'?

murphaph

Personally in a new build I'd install UFH throughout so you don't have rads determining where you put your furniture.

murphaph

murphaph wrote: »

Personally in a new build I'd install UFH throughout so you don't have rads determining where you put your furniture.

I wouldn't like underfloor heating, not here anyway. It could be 13 degrees one day in Winter and 3 the next and back to 13 the day after. It would drive me insane.

air

Deleted User wrote: »

I wouldn't like underfloor heating, not here anyway. It could be 13 degrees one day in Winter and 3 the next and back to 13 the day after. It would drive me insane.

Modern well insulated houses aren't affected by outdoor temperature swings in the same way as older ones, the internal temperature is far more stable.
You might get increased temperatures in rooms with solar gain but it's easy to run the underfloor circulation pump to even this out throughout the house.

My current house will be roasting in an hour with the oil, 2 hrs the heat is off again. I can't argue with that. Then same for the morning, at least this time of year when it's not really cold. I wouldn't be bothered with underfloor heating at least not where I am now. The heat isn't on in the bedrooms really they heat to 18 /19 deg with the rads off and we don't like them any warmer.

A heat recovery system would be good because when the sun shines the south facing part of the house is roasting and the North part not so much. I'd probably prefer this more than underfloor heating.

Water John

Even though I was working in the UFH ind, we never pushed using it upstairs.
Its a personal choice. Need some insulation under it. Also some means of dispersing heat. This could be liquid screed, dry mix or metal pans.

Generally, need very little heat upstairs in modern builds. I would probably put in UFH upstairs myself.

KCross

[Deleted User] wrote: »

I wouldn't like underfloor heating, not here anyway. It could be 13 degrees one day in Winter and 3 the next and back to 13 the day after. It would drive me insane.

I don't think you understand how UFH works.

It's used in conjunction with weather compensation control. Ultimately what you want is constant indoor temp. With proper controls and reasonable insulation UFH gives you that.

You need to experience it before you can say it will drive you insane!

regvw

I am currently starting a new build, just fine my BER.

Honestly the regs now make it mpossible to go with oil, I'll be putting in air to water ufh on booth floors.

The hrv is 5k, that's why I am looking at whether I can afford it or not.

Be interested in who people have used to complete a good job reasonably, pm please

air

Have a look at DCV if you're struggling to find the budget for HRV.

Water John

Reg, that is the reality. Your main source of heat has to be RE.
MHVR is no optional in a sealed new build, essential.

Doorcase

Have looked at good few pumps at this stage and visited some houses. Still undecided. Does anyone know how much a service is for A2W pump. Plumber who installs said he was not qualified to service. Probable need a refrigeration expert

irelandjoe

Doorcase wrote: »

Have looked at good few pumps at this stage and visited some houses. Still undecided. Does anyone know how much a service is for A2W pump. Plumber who installs said he was not qualified to service. Probable need a refrigeration expert

I have a Geothermal and it costs about €150-€200 every 2 years to service.

-Snip-.ie come highly recommended from me.

darkdave265

Doorcase wrote: »

Have looked at good few pumps at this stage and visited some houses. Still undecided. Does anyone know how much a service is for A2W pump. Plumber who installs said he was not qualified to service. Probable need a refrigeration expert

Make sure the people you buy it from are the ones that service it as know one knows the product than people selling and installing it