Monday, 20 August 2012

Home heating – living with what we have...

Our home is fitted with a ten-year old Worcester 15/19 oil-fired combination boiler which provides the heating and hot water.  Where we live, the other three houses also use domestic heating oil as a fuel source.

Unfortunately, domestic heating oil (kerosene 28) prices tend to fluctuate wildly in line with the world oil price.  There was also a step change in kerosene prices just a few years back, with the costs jumping by 50% from around 40p to 60p per litre in just a few weeks during a particularly cold winter period, even peaking at around 75p in some locations for a short time, and nationwide they've never fallen too far below the 60p level since.   Oil prices also suffer much more from 'downward price rigidity' than any other domestic fuel source, i.e. prices are quick to jump upwards on an oil price rise and very, very slow to fall when global oil prices fall.

Added to the facts that the UK domestic heating oil market is totally unregulated (sorry, I said no politics here...) and that most of the country's supply and distribution is in very few hands so that effective competition is non-existent, then those of us with oil-fired heating must simply endure huge annual costs, typically at least a third more than those with equivalent homes using natural gas. 

So what are the options ?  Let's base the comparisons on our annual heating and hot water costs of £1,500, which is an accurate reflection of the costs of last year's oil tank fills.

Natural gas (mains) – there's a newer housing estate within a kilometre or so from our house, and so laying a gas pipeline is possible although the costs of its installation have been quoted at around £3,000 per house.  Coupled to the requirement to buy a totally new gas boiler, and have at least the gas connection carried out by someone else (by law), this would still probably cost well over £1,000 on a DIY basis.  So, more than £4,000 in today's money per house to convert to gas versus a potential annual saving of around £500.  If I were somehow to persuade our three neighbours to also part with £3,000 each, a pre-requisite if a gas pipeline was to be installed, then the payback period on the simplest of calculations would be over eight years, at the extreme end of what I would regard as a satisfactory return on the initial investment.  However, I don't believe all of the neighbours could (or would want to) find this sort of cash, so it's a non-starter.

Natural Gas (LPG) – installing a LPG tank and firing a boiler with propane is certainly possible, but this would require buying and installing a new pressure tank for storage and also a new gas-fired boiler for the heating system.   The tank will also likely need electrical power for its evaporator to ensure that sufficient gas pressure is generated in cold weather.

Even if the costs of the initial investment were justifiable, the sale and distribution of LPG is also an unregulated market and so we're not guaranteed to be much better off even after a large upfront investment.

Solid Fuel – the previous owners of our house installed the oil-fired combination boiler, which is bad enough (a combination boiler, I mean), but they also blocked up the fireplace and removed the hot water tank from the airing cupboard upstairs.  We've since re-opened the fireplace, and removed the old back-boiler ourselves, which we may not have done if the hot water tank had still been connected.   Reinstalling the boiler and rectifying the plumbing etc would be a lot of hassle, as would having to clean-out and light a solid-fuel fire each day for hot water and heating, which seems rather a Victorian or at best an Edwardian pastime.  So, not a practical proposition although we do use the open fire a lot in the winter evenings, it's a very nice feature and supplements the heating a little.

Electricity – heating anything with electricity is very expensive and, if the electricity was sourced from the grid, would cost over twice what we pay now for oil.  What about generating our own electricity ?  Well, by my calculations the house needs a heat source of around 18 kW, and that's way beyond any reasonably-sized solar array (it would need hundreds of square metres of panels to generate enough energy annually), so another non-starter.  I've also disregarded our own wind generation on such a scale, since it would need a very large turbine and, like the solar panels, a huge battery bank to store enough energy to continually heat the house on demand.   Any electrical-powered solution would also need new storage heaters to be fitted throughout the house.

Heat-pump – a ground-source heat pump is a technically viable alternative to oil, but although our gardens are quite large there's not sufficient free land to install enough slinky coils a metre or so below the ground, i.e. the easier option, and so we'd need to sink three boreholes of around 100 metres deep.   Costs would be several thousand pounds, and the system would likely need a second top-up refrigeration cycle just to raise the water temperature sufficiently to use with our existing radiator system.  Low-temperature underfloor heating using water from a single cycle system may be possible, but it's another several thousand pounds to install and the disruption throughout the house is simply not worth it – yet another non-starter.

Upgrade our existing boiler – if we installed a brand-new boiler it might be up to 5% more efficient than our current one, but that's not a big enough efficiency gain to warrant the costs of buying and installing it – the payback period could be decades.

So, having rejected all the alternatives, it seems we're better off living with what we already have.

Remember our mantra, which is only to concern ourselves with what we can directly control.  The domestic oil price may double, or perhaps fall by half (unlikely !), but these are factors totally outside our control.

What we can only reasonably influence, therefore, is the amount of fuel we use.   Let's again look at alternatives to maintain our comfort levels but reduce the amount of heat we need.

Cavity wall insulation – the house already has cavity wall insulation installed.  Although it was done many years ago, and current systems on the market may be very much better, the old stuff is now in the cavity and so again we're probably stuck with what we have.

Loft insulation  we have two roof levels, one above the original two-up two-down house, and another above the large ground-floor extensions which comprise the kitchen, workshop and office.

The lofts are both already insulated, but there's significant scope for improvement and so that's a major step in the right direction.  We're already searching local stores and the internet for special offers, but I think we've left it a little late this year to get a good deal – prices tend to rise as winter approaches and fall in the spring when the stores try to get rid of their overstocking.

New windows – we already have uPVC double glazing throughout but it's more than ten years old, and the newer glass on the market is undoubtedly much better at retaining heat.   However, it's a huge investment to replace 12 windows and 3 glazed doors, even if we're just replacing the glass panels, and so again the likely payback period may make the prospect uneconomic.  Replacing the glass alone is maybe worth a second look, though – it could be done one window at a time to spread the costs over a longer period.

Shielding the house – we are the most westerly of the four houses in our immediate vicinity, and we provide shelter for the other three.  This is definitely a great advantage in almost all aspects of life except for home heating !   The open spaces to the west expose the side of the house to the prevailing winds, and in winter the extra cooling effects of constant cold air movements over the house walls are very significant. 

One option would be to erect a series of tall trees at the western boundary, to shield the house from the effects of the wind.  However, this boundary is around 40 metres long, would require many closely-planted trees to form an effective barrier, and would take years to grow them to a suitable height and density to have any significant effect.  It would also drastically reduce the sunlight falling on the garden, so it's another non-starter for several reasons.

Having looked at what we can't do, then what can we do ?  Well, in addition to improving the loft insulation, there's a series of small measures we can take that cost little to implement, and when used in combination they may have a noticeable affect :-

Fit a room thermostat – we have an electronic controller, but strangely we don't have a thermostat in the central heating system control at present, except for the frost stat near the boiler which is designed to ignite the boiler if it gets too cold, to prevent the water freezing in the pipes.  So we simply rely on the controller timer to switch the heating on and off intermittently, or switch it off manually on the rare occasions it gets too warm. 

So fitting a room thermostat is another top priority, and it won't cost too much although it'll take around 25 metres of mains cable and be a bit tricky to route the cable unobtrusively from the living room to the boiler.  There are wireless versions of room thermostats on the market but there are a few solid brick walls between the two points, and so I'd be a little wary of shelling out for the wireless version and then finding it's useless for our application.

However, a hybrid system is also worth considering, where we run cables from the boiler into the kitchen and install the wireless receiver in a location where we know there are no brick walls in direct line-of-sight with the thermostat.

(Update - October 2012 - we've now fitted a wireless room thermostat using the hybrid system described above.  Seems to be working fine, let's hope it helps reduce the oil consumption...)

Fit individual radiator thermostatic valves – we have only one radiator at present fitted with its own thermostatic valve, so this is definitely worth investigating, but they can be rather expensive and it would help if we could find a job lot of thermostatic valves for auction on eBay, to keep the costs to a minimum.  It means draining down the heating system and maybe a few little plumbing modifications, but it's potentially a job for next summer.

Radiator reflectors – we have eleven radiators in the house, of which seven are mounted directly against outside walls.   In domestic heating systems, the term 'radiator' is something of a misnomer, in that the radiated heat effect is quite small and most heating occurs by convection movements of the air against the hot surfaces.  However, the radiators are mounted close to the wall and therefore it's likely that some radiated heat is lost into the fabric of the building and out through the walls. 

Therefore, we've made several hardboard panels, some of them also lined with expanded polystyrene sheet, and faced them with a proprietary reflective foil barrier.  The panels are then slid into position behind the radiators with the foil side facing towards the back of the radiator.  This reflective stuff can be bought (as radiator foil) on eBay or the local hardware stores for only a few pounds, and so because it's a small investment we thought it's worth a try.

making a radiator reflector panel

Uncover the windows – we have four windows on the south elevation of our house and four (smaller) on the west.   In the winter, there are many days of bright sunshine even though it's freezing cold outside.  Making sure the blinds and curtains are all fully opened during daylight hours should result in a slight solar heat gain to the house.  We're lucky in this respect in that most of the windows are not visible from the road or footpaths and so there's no loss of privacy.

Cover the windows (!) – when it's dark outside, we could hopefully reduce some heat loss from the house by using heavy curtains (drapes) on the largest windows.  It's certainly worth a try on our office / workshop, which was once an attached garage before being converted to a living space, and the entire northern end is now glazed where the up-and-over door used to be.

Isolate unused rooms – we have three bedrooms, of which only one is used on a regular basis.  We intend to install rubber insulation strips (available for just a few pounds) around the door frames of the other two bedrooms and turn the radiator flows down to an absolute minimum (unless we have guests staying, of course).   Draught excluder 'sausages' or 'snakes' made from stuffed cloth placed outside at the bottom of the doors will complete the insulation process.   It's not a good idea to close the radiator valves fully, but just to keep them cracked very slightly open to allow a minimum heat flow into the rooms for protection against frost and condensation.

If you have any water piping and storage tanks in the loft, which we don't because of the combination boiler, you also need to ensure that they're properly lagged if you're reducing the heat in the rooms below.  This also applies when you're fitting additional loft insulation, because otherwise in extremely cold weather you run the risk of pipes freezing and bursting if there's little or no heat coming up from below.

Multi-point door locking – the three external doors to the house are all multi-point locking systems, which is very common in uPVC doors.   When the doors are unlocked during the day then most people (ourselves included) just pull the door closed and leave it latched at the central locking handle only. 

However, simply by raising the handle upwards as if you were going to lock it, the door is pulled much more firmly onto its seals at the multi-lock points and this should help eliminate any small draught paths.

This will take a change of habit, but we'll try to remember to do this every time we close the doors this winter.

Blocking up the cat-flap – the previous owners had dogs and cats, with free access into and out of the house via a cat-flap.  Although the flap can be closed and fixed in position both inside and out, there was still a large cavity through the thickness of the door that we've recently packed-out with insulation material.  Much cheaper than a new door.

Eliminating minor air leaks – we've several points around the house where the outside walls and window frames have been penetrated to allow cables etc to pass through –  I've made a few of these holes myself !   Before the winter, we'll go around and pack insulation material in these voids where possible, and also make sure they're all properly sealed against the weather with silicone.

Dress warmer and turn the heating down ! – the most obvious and simplest solution, although there's a practical limit to how many layers of clothes can be worn.

Hopefully you may also find some of these measures useful, and any other similar suggestions are welcomed.....

No comments:

Post a Comment