Increasing we get asked if we can design a home with all mod cons which is not just off-grid but totally independent from all mains services and back up generator. Is this practically possible?
Yes it is. And you do not have to fill the house with candles and gas lamps or live like the Stone Age.
These are the things you will have to consider:
• Space heating (and maybe cooling)
• Water heating for bathroom and kitchen
• Electricity for light, food refrigeration, and other domestic appliances
• Water for drinking, bathing, flushing, and irrigation
• Sewage disposal
Efficiency is the Key
The basic principal in relation to all of these subjects is efficiency: waste nothing. It is far easier to be more efficient in how you use energy than it is to generate energy.
The Energy Balance of Your Home
Whether it is on grid or off grid and totally autonomous from all main services, an energy efficient home will have been designed with the energy balance of the building in mind. This means looking at how the building will be used in different seasons, how many people live there and what they will be doing. Every factor in the design affects the other factors. Change one of them and you have to change the others to maintain the energy balance: the orientation, volume, insulation, airtightness, renewable sources, and so on.
Here’s an article on Holistic Design and why it’s important.
An airtight well insulated home with mechanical ventilation and heat exchanger (HRV) will quite possibly need no heat source at all. Body heat, with perhaps some cooking heat, can be enough to heat the home. Thats because no heat escapes. Bear in mind that a mechanical ventilation system, which is essential in an airtight building, will need electricity so if you are planning your home with no heating for the space and are relying on an HRV, then you need to make sure you are generating sufficient electricity.
If you are planning a renewable heat source for space heating there are various sources to choose from. A biomass heater will require pellets, olive pips, almond shells or plain old wood. Air and ground source heat pumps will require some electricity which needs to be factored in. If these sources are impracticable for whatever reason then you may need better insulation (or be prepared to put on an extra jumper!).
If you’re in Spain, especially if you are on the Mediterranean coast, then you can reasonably expect to spend most of the year living comfortably in shaded and ventilated outside spaces with no need for space heating.
For cooling there are a number of passive features that can be incorporated into the design.
Here are a few articles if you want to know more about some of these subjects (click on them to open):
Mechanical Ventilation and Heat Recovery In Spain
Biomass Heating Systems
Space Heating and Cooling with Heat Pumps
Air Powered Air Conditioning How Cool in That?
Underfloor Heating in Spain
Healthy Heating Systems in Spain
Hot Water for Kitchen and bathroom
Solar hot water is very practical in Spain even in the winter . If you are using a renewable source of energy such as biomass or heat pumps then these systems can be integrated to augment your solar hot water system.
An electric emersion heater should probably be avoided unless you have substantial electricity generating systems.
Find out more here: Domestic Hot Water From Solar Energy in Spain
Try to avoid using electricity to cook with if possible. It’s expensive in energy generation terms.
Butane gas may be an option if you have a good supply.
Otherwise its barbeques! Cooking outside in the summer has the advantage of keeping the heat outside the house and in the winter this is a disadvantage. It’s the other way around in winter. These considerations need to be part of calculating the energy balance of your home.
Slow ovens using hot ashes underground work beautifully. I’ve been looking for an opportunity to write about digging a hole for roasting ever since some friends of ours produced a delicious roast lamb lunch this way.
Electricity for light, food, refrigeration and other domestic appliances
The convenience and magic of an on-grid electricity supply and modern electrical appliances would have been hard to imagine a hundred years ago. Is it possible to live a 21st century lifestyle off grid and without a generator?
Yes. It requires planning. You will need to size your system to cover your needs: fridge, microwaves, toasters, TVs computers, HiFi. Forgive me for stating the obvious but calculate how much electricity you consume and size your electricity generation and storage system to cope with it.
Washing machines, dishwashers, tumble dryers consume a lot. The big one, the swimming pool pump, is an absolute guzzler. You can use the hair dryer because it’s only on for ten minutes. The swimming pool pump consumes the same but is on for hours. If you want a pool a natural swimming pool, (the subject of a future blog post) is the obvious answer. The plants you use to clean the pool need to be appropriate to the micro climate you live in.
If you are planning not to have a back-up diesel generator then start my looking at your natural resources. What have you got – sunshine, wind, hydro-electric? Which you choose will depend on the local conditions. A hybrid system is probably wise such as PV / Wind turbine. Perhaps when it’s not sunny it’s windy and vice versa.
You will need battery storage so you can use the electricity when you need it rather than when it’s being produced. How many days will storage should you have in your battery? This will depend on your consumption rate and any budgetary constraints.
The fact is that nearly everybody who goes off grid backs up their renewable energy source with a diesel generator which solves all problems, such as getting the calculations right and a succession of windless overcast days when you aren’t generating much power. However for the good life (some people see diesel generators as noisy dirty and consume expensive fossil fuel) this maybe against the rules and doing without a generator can be done with planning.
Here are some further articles which might help:
Water for drinking, bathing, flushing, and irrigation
If you are off mains water your sources will be wells, streams and rainwater harvesting. Wells and streams are highly regulated in Spain. Check these out before you buy your site. Rainwater is normally used for irrigation but can fairly easily be made drinkable with some treatment.
On Site Sewage and Waste Water Management
The Good Life
On the question of how to grow your own vegetables, keep chickens, and butcher a pig I am afraid I am not qualified to advise. I do have a book on my shelf from the 1950’s called Practical Rabbit Keeping which I could lend you. If you’re going rural in Spain there will be no shortage of local people with experience in how to turn a pig into chorizo and salchichon.
Author: John Wolfendale
Bio: John is a founder of Eco Vida and is passionate about bringing modern design and construction practices to Spain. He believes a home which is warm in winter and cool in summer is largely a matter of design and selective use of materials. He is British and a Chartered Surveyor with 19 years experience living and working in Spain.