Heat pumps

dermot k

Hi, looking for comments from anyone who has installed the mitsubishi ecodan heat pump in their home recently, ideally one installed in a bungalow around 20years old with good levels of insulation in the house, thanks, Dermot.

Lenar3556

dermot k wrote: »

Hi, looking for comments from anyone who has installed the mitsubishi ecodan heat pump in their home recently, ideally one installed in a bungalow around 20years old with good levels of insulation in the house, thanks, Dermot.

The one general point I would make is to tread carefully;

Heat pumps do work well in highly insulated new builds, but often the heat loss in older buildings is too great to make them a viable option.

My house is about 15 years old and would have had enhanced insulation at the time, but nothing like a new build today. I did look at a heat pump recently but decided against. The purchase and installation cost, running and maintenance costs made it a significantly more expensive proposition vs oil.

I am interested in heat pump technology, can see it being a significant part of future heating solutions, but for the time being, it didn’t stack up for me. I did get a heat pump tumble dryer which I’m very happy with!

dermot k

Thanks for your reply,it seems like insulation is the main thing and the newer builds, thanks, Dermot k

stiophan

While oil prices (and thus heating oil) has remained low, the fact is that carbon taxes will rise every year until at least 2030 (or until our demand for heating oil falls). There are two choices then- accept your home heating bill will rise every year (and thats just hoping that wholesale oil prices will not rise as well) and invest in ever greater amounts of insulation. Options here are external insulation cladding, cavity wall insulation injection and optionally ultra low energy windows (three pane or similar 2 pane). The alternative is to get a bER assessor to recommend what level of extra insulation is needed in order to consider a heat pump.As you note, without extra insulation, a heat pump will not work (and no SEAI grant without boosting the BER rating). Another option is heating assistance ie adding solar thermal panels to your roof and using that heat assist to cut your oil bill. Note it would still need an insulation upgrade to obtain an SEAI grant for roof thermal ( or solar PV and either dump the excess power into heating the water tank or focus most of the power at heating the water and the "excess" at cutting your power bill.
I would recommend the insulation option. In a 15yr old house there is plenty of options to insulate further (insulating under the floor boards). Just presume the original builders never heard of insulation at all.

3d4life

stiophan wrote: »

.... There are two choices then- accept your home heating bill will rise every year (and thats just hoping that wholesale oil prices will not rise as well) and invest in ever greater amounts of insulation. Options here are external insulation cladding, cavity wall insulation injection and optionally ultra low energy windows (three pane or similar 2 pane). .....

There is a third option which is relevant to many many house. That option is to recognize and accept that the house may be beyond economic renovation. Simplistically, compare the cost to knock and rebuild to the cost to upgrade.

MicktheMan

stiophan wrote: »

While oil prices (and thus heating oil) has remained low, the fact is that carbon taxes will rise every year until at least 2030 (or until our demand for heating oil falls). There are two choices then- accept your home heating bill will rise every year (and thats just hoping that wholesale oil prices will not rise as well) and invest in ever greater amounts of insulation. Options here are external insulation cladding, cavity wall insulation injection and optionally ultra low energy windows (three pane or similar 2 pane). The alternative is to get a bER assessor to recommend what level of extra insulation is needed in order to consider a heat pump.As you note, without extra insulation, a heat pump will not work (and no SEAI grant without boosting the BER rating). Another option is heating assistance ie adding solar thermal panels to your roof and using that heat assist to cut your oil bill. Note it would still need an insulation upgrade to obtain an SEAI grant for roof thermal ( or solar PV and either dump the excess power into heating the water tank or focus most of the power at heating the water and the "excess" at cutting your power bill.
I would recommend the insulation option. In a 15yr old house there is plenty of options to insulate further (insulating under the floor boards). Just presume the original builders never heard of insulation at all.

May I respectfully suggest you do a bit of research into the more important role lack of air tightness has to play in the heat loss from a typical Irish house. It is not all about insulation in our climate.

stiophan

Insulation drives better air-tightness. Better low-e Windows, cavity wall insulation etc all improve air-tightness naturally. Every higher level of insulation added, cuts air-tightness at some level-some at a higher level than others. Naturally big holes in your home will kill retaining heat. Any competent BER assessor should show you where all that heat is going (and some advice on whether it can be fixed or not). I presume your research would have understood that.

MicktheMan

stiophan wrote: »

Insulation drives better air-tightness. Better low-e Windows, cavity wall insulation etc all improve air-tightness naturally.

Great.
Any data on the impact that cavity wall insulation has on airtightness as an example?

stiophan

https://en.wikipedia.org/wiki/Spray_foam
see properties- thermal resistance. Also see Convective heat transfer for notes on air tightness. US surveys show some cavity filler compounds cut external noise by boosting air tightness (which also cuts heat loss)

MicktheMan

Seriously ... Wikipedia??

Are you really advocating using such a spray foam product in a cavity wall?

:eek:

corkgsxr

tommymac86 wrote: »

Heat pumps offer great heat

They actually dont. They rely primarily on not losing the heat in the house. There small output over longer time

If you insulated your house to heat pump levels anything will be cheap to heat it.

monseiur

corkgsxr wrote: »

They actually dont. They rely primarily on not losing the heat in the house. There small output over longer time

If you insulated your house to heat pump levels anything will be cheap to heat it.

A cost benefit analysis on the following would be very interesting :

Take say a 15 year old bungalow / detached house with standard insulation, standard double glazed windows etc. and oil fired central heating.
Upgrade all insulations, replace all windows & doors with triple glazed uPVC or similar to bring house up to today's required standard
Replace OFCH with air to water pump and related stats, TRV's etc etc.

Assuming air to water pump has a lifespan of between 15 to 20 years I would hazard a guess that leaving well enough alone would save a big fistfull of dollars over say 20 years.
No doubt in 20 years time air to water pumps will seem as out dated as OFCH seem today. One should think twice before jumping on the next band wagon that comes rolling by, most are driven by drivers with self serving agendas !

Our climate is not cold, the thermometer hardly ever falls below freezing, in comparsion to say mid west USA and Canada but dampness is our problem both summer and winter.

corkgsxr

monseiur wrote: »

A cost benefit analysis on the following would be very interesting :

Take say a 15 year old bungalow / detached house with standard insulation, standard double glazed windows etc. and oil fired central heating.
Upgrade all insulations, replace all windows & doors with triple glazed uPVC or similar to bring house up to today's required standard
Replace OFCH with air to water pump and related stats, TRV's etc etc.

Assuming air to water pump has a lifespan of between 15 to 20 years I would hazard a guess that leaving well enough alone would save a big fistfull of dollars over say 20 years.
No doubt in 20 years time air to water pumps will seem as out dated as OFCH seem today. One should think twice before jumping on the next band wagon that comes rolling by, most are driven by drivers with self serving agendas !

Our climate is not cold, the thermometer hardly ever falls below freezing, in comparsion to say mid west USA and Canada but dampness is our problem both summer and winter.

Heat pump units are failing in as little as 7 years. Imo youd be very lucky to get 15 years.

You can do the theory and in theory youll save a packet with a heatpump.

But they arent that efficient in real life. Thats why unless the house is super air tight they dont work.

Which brings back my point. Its not the heatpump thats efficient. Its the house

Calahonda52

3d4life wrote: »

There is a third option which is relevant to many many house. That option is to recognize and accept that the house may be beyond economic renovation. Simplistically, compare the cost to knock and rebuild to the cost to upgrade.

Simplistically, it takes 64 years to get back the CO2 emissions from a new build vs a refurb.

Calahonda52

stiophan wrote: »

Insulation drives better air-tightness. Better low-e Windows, cavity wall insulation etc all improve air-tightness naturally. Every higher level of insulation added, cuts air-tightness at some level-some at a higher level than others. Naturally big holes in your home will kill retaining heat. Any competent BER assessor should show you where all that heat is going (and some advice on whether it can be fixed or not). I presume your research would have understood that.

Wrong
I presume your research would have understood that.