Off Mains: The Costs

Whilst almost everyone has access to mains water and electricity, there are many villages and isolated rural homes which don’t have access to mains drainage and mains gas. If you are considering such a plot, how much extra are you going to have to pay? And what are the additional costs of being ‘off everything’?

Off-Mains Gas

First, check how far off the gas mains your property is. Sometimes the mains have been laid to nearby residences and National Grid (who handles most of the UK’s gas connections) will lay on extra pipe to get your site on the mains. Obviously this is price dependent, but there is no harm in obtaining a quotation. Generally speaking, a mains gas connection is well worth having.

If mains gas is not available at a sensible price, what are the alternatives? You have to find a credible method of heating your home and hot water. The options are:

Oil

Oil-fired heating was the preferred option for most rural self-builders until about five years ago when the oil price started spiking. It still has a lot going for it because it’s widely understood and there are a wealth of suppliers both of boilers and heating oil.

• Pros: It’s simple to understand and there’s lots of rural suppliers and servicers.

• Cons: Oil has quadrupled in price in the last ten years and people naturally fear this trend will continue. It used to be cheaper than gas, now it’s twice as much (and only half the price of electricity). It requires storage and you can’t cook with it. Compared to gas, installation cost is around an extra £2,000 and running costs are high.

LPG (Liquid Petroleum Gas)

This used to be the main alternative to oil, but less popular due to the expense. Not so anymore. It is also arguably more versatile than oil. You will, however, have to install a large unsightly tank; although at a greater cost this can be installed underground. The financial calculations are similar to oil.

Electricity

Electric heating used to be frowned upon as extremely expensive and rather wasteful, but electricity seems to be becoming fashionable, especially if it’s used to power heat pumps, which promise significant savings on heating costs with running costs on a par with mains gas:

• Ground-source heat pumps: They are expensive to install (upwards of £12,000, about two to three times as much as an oil-fired system) and require an area three times the size of the heated footprint to draw ground heat from, so are not suitable for many sites. You should undertake a survey of the site before you go ahead.

• Air-source heat pumps: They are much cheaper to install and take up less space than ground source, but are not as efficient and can be noisy.

Biomass

Biomass solutions range from woodburning stoves used to boost other heat sources, to state-of-the-art wood-pellet boilers which can cost as much as ground-source heat pumps. Such boilers come fully automated so that you don’t have to manually re-fuel, but they require large storage facilities. Running costs are relatively cheap.

Solar Thermal

Solar thermal provides a credible source of hot water through the summer months, but is not as effective in the winter. It’s therefore only a partial solution.

Energy-Efficient Fabric

Another option is to build high levels of energy efficiency into the house and reduce the amount of energy required to provide space heating, such as a combination of a woodburning stove, electric heaters and a whole-house ventilation system. At ultra-efficient levels (i.e. PassivHaus), you can usually dispense with the stove, though you still need a heat source to heat water.

Off-Mains Drains

There are well-worked routines for dealing with sites off the main drainage systems. The simplest is to use a septic tank with a large drainage field built under the garden. Where this isn’t possible, a treatment plant is advised. Though more expensive (£5,000 vs. £2,000), they don’t require so much in the way of excavation.

The additional cost of off-mains drainage solutions has to be set against the cost of mains drain connections, which can vary from a few hundred to thousands. In fact, there are many sites where site treatment will work out less expensive, though a house with a mains drain connection is worth more. On-site treatment requires servicing and the tanks need emptying once a year.

"I Had No Services At All!": Inchdrine Lodge, Marina Dennis’ self-build, is situated in the beautifully secluded Cairngorms National Park — however, the isolated setting did create unanticipated costs: “There are no public services whatsoever, so we have a septic tank and a private water supply also serves my own house. We had to bring it 310 metres across the field and dig a trench to put in the water, as well as the electricity and telephone,” explains Marina. “When I applied for an electricity supply I was informed that the transformer in the area didn’t have sufficient capacity, so I had to pay for a new high-voltage line. This was hugely expensive — £9,600.”

Off-Mains Water

Some isolated sites have to provide their own water supply, usually achieved via a borehole. Costs for boreholes vary widely (£2,000-£25,000) depending on how deep you have to go. You are also responsible for your own water treatment and have to carry out various tests for the Environmental Health inspectors. You must also consider the issue of ground contamination and bear in mind that borehole drinking water doesn’t go well with septic tanks!

Off-Mains Electricity

Very isolated sites may be inaccessible to mains electricity. Power is often drawn through a mix of on-site solar photovoltaic panels and wind turbines (such sites tend to be in windy locations), combined with battery back-up and diesel generators for times of peak demand. By their very nature, these sites tend to get snowed in on a regular basis and, combined with the ongoing costs of maintaining access along unadopted roads, the cost of going totally ‘off mains’ in this instance can be enormous — both in terms of set-up costs and ongoing expenses.

What About Grants?

From July the Government is offering grants via the Renewable Heat Incentive Premium Payment for the following heating systems: solar thermal (£300), biomass (not woodburning stoves - £950), ground-source heat pumps (£1,250) and air-source heat pumps (£850). Check out est.org.uk for more. Tariffs kick in from October 2012.