Wouldn't it be great to be able to harvest space heating from the renewable technologies we spoke about in the earlier project? A joined up approach would be even better, such as using the electricity generated to provide power for a heat pump or boiler so that the energy we get is truly free. Lets see what options are available to implement space heating, based on renewable technologies. 

My own house is based on a traditional radiator system with an oil fired boiler. My plan is to migrate from this system, perhaps in a staged approach, so that the impact on my wallet is reduced. However, I am not at all sure sure if doing it in a staged fashion actually saves money; perhaps it may be better to go for a complete new system all at once?  Whichever road I take, the destination is the same; a renewable space heating system which in turn reduces my heating bills.

I decided to create a list of the current heating technologies, to use a basis for my target solution. It is not exhaustive but illustrates the main points of each system:

Perhaps I am oversimplifying here, but there are benefits and drawbacks to all systems. There is no single system that ticks all the boxes, in my view. For example the very concept of a low and widespread heat using under floor pipes is opposite to the quick heating high temperature radiators system. It follows that I will be particularly cautious of anyone advocating that their system is the best and has no drawbacks.

Renewable Energy Grants:

The Sustainable Energy Ireland organisation has made available, via government funding, a set of grants for homeowners to install these alternative heating technologies. They range in scale from the simplest system, such as a standalone wood pellet stove, to the larger geothermal based systems. In each case there is a sliding scale of grant available. Whilst this will encourage many people to upgrade their heating supply, using registered installers means that a lot of the money spend is simply covering the installation cost of the system, as opposed to the system itself. I have nothing against this in principal, but would have welcomed the option to also avail of the same level of funding if I elected to buy and install certain systems myself (within reason).

As a guide, the grants range from EUR1,100 if installing a wood pellet stove up to EUR6,500 if installing a vertical ground source heat pump. In some cases you can avail of 2 grants if you install particular system combinations. Given an example guide price of EUR18,000 for a ground source heat pump system, this would cover over 30% of the cost. 

The Staged Approach:

Altering the heating system in stages is probably not the best way to achieve the best economic gains, because the plumbing and fitting costs will be payable each time the system is upgraded, rather than paying once.

The obvious fist step for me would be to replace the oil boiler with a wood pellet boiler. That would make me no longer dependant on a fossil fuel, and I would also avail of a grant to help me with the installation cost. I estimate the cost of this to be around EUR6,500 to me, after the grant has been factored in. I am also allowing for costs to build a storage area to house the pellets, a thermostatic mixing value and new flue.

My medium term plan was then to upgrade to an under floor system, not because of any particular love of the product but because it will be cheaper to heat the house by using lower temperatures over a larger area rather than the high temperatures required for radiators. I would estimate the cost of this to be around EUR15,000, to allow for floors to be dug, piping laid and necessary manifold connections back at the boiler.

The long term solution could then be to install a geothermal heating source, backed up by the wood pellet boiler if required. However, in partnership with that, I would also want to investigate the option of powering the heat pump itself by renewable electricity, rather than from the GRID. That would give me truly free heating when not using the backup pellet boiler. I estimate the cost of this to be around EUR20,000, allowing for ground works, heat pump, and additional photovoltaic solar panels and inverter to handle the current required from the heat pump.

That's a huge amount of money if you add it all up. I wonder if this staged approach is really the best solution?

The Big Bang Approach:

Alternatively, I could get quote from some companies for moving to geothermal underfloor with a wood pellet boiler to provide the energy source. I estimate that the whole conversion could cost upwards of EUR25,000. But this could also be cheaper than opting for a phased solution. My concern is also that, while geothermal and similar based heating systems operate well and deliver low to medium temperature ranges, they use both a high amount of electricity and the heat pumps themselves also require very high start up wattage, which would make it very difficult to run from a renewable energy source.

Lets look in more detail at each type of system, before making our decision. Lets begin with wood pellets.