home heating options.... please save me !

I suppose at the time in 2004 other than the environmental reasons, we were thinking we would rather be at the mercy of the ESB than the price of oil on a stock market, some would say that was a mistake I suppose, others wouldn't. The other benefits are not running out of fuel and never having to worry about topping up...
 
I dont see how it was a mistake as clearly it works for you & who knows what way oil is going to go in terms of supply or cost ! I def think the future is renewables & heat pumps but Im still to be convinced that the current heat pump systems are worth the massive initial cost. having said that it would be fairly easy for you to up grade. shoestring do you mind me asking how responsive is the system ? For example if you decide you want a quick blast of heat is this possible ? When the temp hits below zero how effective is it ? How much do you have it on every day ?
 
....I don't really get the heat pump type heaters......

1. Heat pump produces generally 3 - 4 times the amount of heat energy than it consumes That means a kWhr of heat cost around 5c during the daytime.

2. Night rate electricity is about half the price of day rate so a kWhr of heat at night is circa 2.5c ( which is quite a good price )

If you have underfloor heating the thermal inertia of the floor is very high this means that if you heat the floors at night they will be warm during the day

At least that is the idea of it as I understand it
 
I get the idea and can see why its good environmentally but if you are looking to save money it sounds like there is little ot no saving to me (over oil/gas), I think it could cost more?.

So the saving is based on heating the house all night and it retaining the heat during the day?
I can't see how this suits people who are not in the house during the day.
Is the house not far too warm during the night?
Might be good for office/commercial appliccations but less so for domestic?

The heat is mostly on during the day when the rates are high. For the 5 cents you pay during the day you could get the same heating from oil/gas. Day rates for electricity are higher than normal (slightly) if you have night saver installed.
 
corkgal said:
..............................I can't see how this suits people who are not in the house during the day.
Is the house not far too warm during the night?...........................
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FWIW I agree with you. Nevertheless many people seem to be happy to live in houses with this sort of heating arrangement.

It probably comes down to having a house with very low heat loss and managed ventilation
 
Is that really how it operates ? I mean is it not possible to regulate the heating system so you have the heat on for when you actually want it ? That seems very strange. each Zone has its own thermostat & I thought most individual rooms were zoned ?
 
You can probably have the heat on when you want, but it will just use the standard rate electricity. To make savings over gas/oil you would need to run the system off nightsaver. (Gas/oil is 4 times cheaper per KWh than standard rate electricity, heat pump uses 1 kwh of electricty to generate 4 kwh at max efficiency))

There are two ways to run these systems:
1. Instant heat = the electricity rate that applies at the time = same price as Gas/Oil. This is how normal gas/oil central heating works.
2. Using house, floors as storage heater, uses nightsaver electricity but heat is on all night and during the day, you may want heat on in the evenings only (if you are out working). Potentially half the price of Oil/gas but may not suit you lifestyle.
 
sorry for being thick here corkgal but would it not be more efficient to have the heat on very low temp when you not in the house & then to increase temp before you come home in the evenings for a couple of hours ?
 
If you boost it during the day time then its full price electricity, so your cost saving is gone.
It should make it more comfortable though.
 
corkgal said:
I get the idea and can see why its good environmentally but if you are looking to save money it sounds like there is little ot no saving to me (over oil/gas), I think it could cost more?.
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It is much less enviromentally friendly than you would be lead to belive.

There are 13 power stations in Ireland and 7 of these burn fossil fuel to create energy. Not bad, just over half, sadly these 7 stations create about 85% of the country's power. Leaving the 6 hydro stations pick up the last 15%.

Least not forget, these 7 stations are no more than 45% efficient, so of the energy created only that percentage is harnessed.

People pick geothermal for lots of reasons, Don't let the enviroment be one of them. It is simply untrue.

Until we get the majority of our power from a renewable source geo will harm the enviroment more so than a condensing oil/gas/wood pellet boiler.

It is also expensive to install and run. I would not fit it in my new home.
 
Playing devils advocate here but I suppose you could always signup to airtricity who claim 79% of thier energy is from renewable sources ?
Does an air to water heat pump not compete reasonably with any other underfloor heat system to install ?
With regards to the cost of running air to water heat pumps whilst it is difficult to get exact data, a poster on another thread estimates it will cost him 2000 euro for all his heat, hot water & electricity for the last year in a 2900 sq foot house (including the cold snap at christmas). It is hard to see how any system would cost much less than that ? Thats not even taking into account future oil & gas reserves/prices. I was always more in favour of traditional heating systems but its certainly food for thought ?
 
Just to backup kemosabe's statement, that other poster is me. You can't compare running costs of a heat pump to oil/gas directly on a like for like basis, as they work on different principles. An oil/gas system is primarily used as an on/off system for selected durations. A heat pump by comparison runs all the time (although can be set to not run at a given outdoor temp).

In my case, the years running cost is constant heating. The oil/gas alternative for the same running period would be considerably higher, so does provide cost savings.
 
dj01 said:
Just to backup kemosabe's statement, that other poster is me. You can't compare running costs of a heat pump to oil/gas directly on a like for like basis, as they work on different principles. An oil/gas system is primarily used as an on/off system for selected durations. A heat pump by comparison runs all the time (although can be set to not run at a given outdoor temp).

In my case, the years running cost is constant heating. The oil/gas alternative for the same running period would be considerably higher, so does provide cost savings.
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Valid points, but our weather does not support such a heating system. If you needed to run your heating constantly from oct through to april, than maybe I would consider fitting it.
We could get a cold snap in august, and as you know switching your heating on for an hour is not an option.

Could you please answer these questions for me,

How big is house and how much did it cost to have geo and UFH fitted?
thanks.
 
As I understand it (& maybe dj01 can verify this), the system could cope very well with a cold snap in August. Say for example the weather has been ok & no need for central heating & then as you say you get a cold snap of 4-5 days. Well as it has been explained to me during the warm period you would have had the heat pump running at minimal just to keep the water in the buffer tank at a pre set minimum temp then when the cold snap hits the system can be boosted (manually or automatically) to produce adequate heat for as long as necessary then you can return to running at minimal. During these warm periods you can run the system for however long you require at night time availing of night rate electricity & you can `call` the heat as required.
Yes you may have the system on more often but the cost of that is off set against the on off function of other heating methods & as we all know it requires far more energy to heat from cold than it does from warm.
I hope I have explained that ok but as I said those with the sysyem could certainly explain it better.
 
Buffer tank vs heat held in the house/floor.
In one of the posts higher up a poster said that the heat is held in the house, so whats the buffer tank? Does this store hot water, heated from nightsaver and then released during the day/ evening?
 
Kemosabe,

I dont mean to muddy the waters ( or be Devils Advocate ) but if I were in your position of initial planning a new build of a low heat loss house I would be thinking of a heat pump, a heat recovery unit and one ( or more depending on heat loss calculations ) wood burning stoves

The heat pump that I would be thinking in terms of would be an air - air unit. Perhaps something like

[broken link removed]

This type of unit seems to be remarkably efficient for spring / autumn but will probably struggle a bit ( due to defrost cycle ) on cold winter days

I would have the heat recovery duct work sized to function as a ducted hot air heating system and use a heat recovery unit that integrates with the heat pump e.g. one of these

[broken link removed] )

The wood burning stove(s) would be to supply additional energy to the heat recovery unit on cold winter days

One negative is that you dont get hot water from this system

One positive is that the system can also be used to cool the house in summer

Having said all that I would doubt that Mitsubishi would be the best choice for Ireland. I have yet to meet an Irish Mitsubishi dealer / installer with any interest in servicing the residential market. There are other brands ( Daiken, Toshiba, Panasonic, Fujitsu ).

HTH


Olddog
 
Hey Corkgal I have to keep stressing that I am far from an expert & I dont work in the area. I have done a fair bit of research & met with & spoke to a lot of people with different systems. I visited a house last week & saw an air to water system in operation with a buffer tank. As far as I understand it the buffer tank is exactly what you said above. It is a sizeable water tank that is very heavily insulated & stores the water heated by the pump. It holds the water before it goes to the underfloor heating in the house. The system is a circuit so the water returns to the bottom of the buffer tank having lost some of the heat.

No problem Olddog really appreciate the input. I definately intend to go with a heat recovery system & a wood burning stove. Am pricing a Daiken pump at the moment & saw a PZP one last week. I know nothing about air to air heat pumps so thanks for the link I will check it out.
 
Not an expert either, just interested to see how this works and if there are any real savings.
 
At the start of this thread I was just seeking information but if Im honest deep down I had planned to go with oil, rads & stove back boiler. However as time goes on & the more people I meet & speak to I am more interested in the air to water system. I have been to two homes with it in operation & both these people are very happy & they believe they are making a small saving for very comfortable underfloor heat & hot water.
That in itself is something, however when you factor in the uncertainty re: future oil & gas reserves/prices it makes it more appealing. In addition as one plumber I met with pointed out to me, technology in this area is the future & is making huge strides. He believes in say ten years time there will be a much more efficient air to water pump available. Having it put in now will make it much easier (& cheaper) to retro-fit when the time is right.
I dont think the system is perfect & I am going to keep an open mind & try gather as much info as possible before I have to make the final call. So any horror stories out there re air to water or any other info, Im all ears ??
 
DavyJones said:
Valid points, but our weather does not support such a heating system. If you needed to run your heating constantly from oct through to april, than maybe I would consider fitting it.
We could get a cold snap in august, and as you know switching your heating on for an hour is not an option.

Could you please answer these questions for me,

How big is house and how much did it cost to have geo and UFH fitted?
thanks.
Click to expand...

The system monitors outdoor temperature and the heat pump has a cut off temp setting, you simply set at what ext temperature you want heating to commence, if the temperature start falling the heating starts running at whatever internal temp you've set.

House size is aprox. 2900sq ft. To be pedantic, it's not strictly geothermal, as it doesn't use ground collectors to take heat from the earth. The system cost inc. commissioning was in the region of 13k which includes the UF heating system throughout the house. There's also a grant for heat pumps including air source available from SEI.

One of the great aspects of the system we really like is that there heating is far more universal throughout the house, unlike rads where you can get cold spots that just don't heat as well.

It suits our needs very well, but each person will have different needs and priorities, so what works for one may not for the next.
 
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