Living in an Off-Grid Solar House – The Good, the Bad, and the Ugly

I built my off-grid solar home with my husband in 2003. The house was originally powered by a combination of solar and wind power. Living off-grid is an interesting experience.  Everything you do – cook lunch, have a shower, watch TV – it’s all powered by the sun or the wind. A pretty cool feeling – most of the time. Let me introduce you to the GOOD, the BAD and the UGLY.

We experienced them all one January in 2006. January 23 was clear and cold. A bitter wind raged through the bare trees and whipped the snow into eddies and drifts.  But for us, it was still a good day because the sunshine and horrendous winds gave us a record day for power. Not all days are like that.

This is what that a good day looks like to us:

A Good Day for Solar and Wind Power

A Good Day for Solar and Wind Power

You can see the sun rise in the first chart, see it start to produce more and more power until solar noon, then decrease again till sunset – a nice uniform curve. The jagged dips are from wisps of cloud crossing the face of the sun. The second chart shows the wind power – it is recorded in short intervals and what you see here in red is the maximum and minimum power for each interval, with a line in the middle for the average. You can see how variable the wind is, compared to the solar – it’s not the steady line or curve that you might expect.

That night the wind started to die down and the next day started out cloudy, with some clear sky later in the day.

A Bad Day for Solar and Wind

A Bad Day for Solar and Wind

But this is not the worst it can get. Imagine a day with no wind and it’s snowing. Here it is – the UGLY day.

An Ugly Day for Solar and Wind

An Ugly Day for Solar and Wind

Fortunately, we don’t see many days like this – but notice, there is still some solar power, even when it’s snowing.  It is for days like this that an off-grid system has a large battery bank to see you through. In January, however, that may not be enough to carry you through all the bad and ugly days so a backup generator is also part of the system.

This is what the whole month of January can look like (2006 had an unusually cloudy January).

Our Solar and Wind Power for January 2006

Our Solar and Wind Power for January 2006

The yellow bars show the solar power we received, and the blue bars represent the wind power. Add the two together and you have the total power. You can see January 23, the GOOD day, as a very tall bar – we produced 12 kWh of power that day. We only need 5 kWh a day to run our house so we stored the extra in our batteries. The next day was the BAD day – you can see how short that bar is in the chart. The UGLY day was January 13 – a very short bar indeed.

This was the worst month of the year. Most months there is plenty of sun and wind to supply all the needs of our home. That is the story with off-grid homes – you can store power for a few days, but there is no way to store all the extra power from the summer for months like this. That is the big difference between off-grid and grid-tied systems. Grid-tied systems are connected to the utility grid and, where net metering is offered, you can use the utility grid to “store” excess power that you produce in the summer for the winter months. This is done by giving you credits on your bills for the extra power.

As I am writing this, we are having one of those ugly days. Our wind turbine is not turning and we are having our first snowfall of the season. But it’s been a long and beautiful summer and fall. Like farmers, we have to work with the vagaries of the weather, but we enjoy the rewards of being self sufficient, environmentally friendly and never having a power outage.

 

Gardenview Solar Home

The Gardenview solar home is an example of  a passive solar home that fits on a city lot.  It was designed by Suncatcher Solar and built in partnership with Jaylin Homes in Saskatoon, Saskatchewan.

It features energy efficient building construction, radiant in floor heating and a solar power system.

Passive Solar Design

Living room in late October

Living room in late October

The south side of the completed home, shown here, faces the back yard, where the owners are planning a large garden.  Normally the south wall is the long wall of the house but the shape of the house was constrained by the size of the lot.  Despite these limitations, however,  the home’s south windows are 9%  of total floor area.

Stone facing stores the winter sun's heat

Stone facing stores the winter sun’s heat

Abundant sunshine into the house warms the home during the winter.  The roof overhangs keep the sun out in the summer, when the sun is higher in the sky, so that the house stays cool.  Thus, a passive solar home typically does not need air conditioning in the summer.  Stone facing on the fireplace and a granite countertop act as a thermal mass to store the winter sun’s heat for overnight.

Wiinter and Summer

Wiinter and Summer

North side of Gardenview home

North side of Gardenview home

The attached garage is on the north side of the home, with the bedrooms above.  Fewer windows are needed here, increasing the energy efficiency of the home.

Energy Efficiency Features

The bitter cold winters in Saskatoon, plunging to temperatures as low as 40 degrees below zero, make energy efficient building methods an important component of the passive solar design.

Upper floor landing

Upper floor landing

The Gardenview is built with wood frame construction with 2″ x 6″ walls and blown-in insulation.  Themal bridging – heat lost through the wooden framing members – is a major source of heat loss in this type of construction.  The Gardenview reduces this heat loss with 1″ foam board insulation applied to the inside of the exterior walls.  The inside of the foam board is faced with a reflective foil to reflect heat back into the home, cutting down on heat loss through radiation.  An air gap between the foil and the drywall is essential to make this method effective and can cut down on radiation losses.

Heating System

A woodburning fireplace provides renewable heat

A woodburning fireplace provides renewable heat

Radiant in floor heating on all levels of the home supplements the passive solar heating.   The attached garage also includes in floor piping, but the temperature is kept considerably cooler than the house.  A wood burning fireplace provides extra heat and ambience on cool evenings.

The in floor heating is supplied by a Wiessman natural gas modulating boiler.  The system uses a sophisticated central controller to program the heat requirements of the home.  The in floor system has a continuous flow and is automatically adjusted based on the reading from an outside temperature sensor.  When the outside temperature goes down one degree the temperature of the in floor system is increased by 0.7 degrees or whatever the controller is programmed to.  This can be adjusted to suit the preferences of the occupants.  A fine tune control knob lets the homeowner make minor adjustments as needed.  The advantage of this sytem is that, once it is set, it usually does not need to be adjusted often and the continuous flow means that the boiler can operate at a lower level (typically 25% of its maximum output), thus saving energy.

Bruce explains the in floor heating system to the homeowners

Bruce explains the in floor heating system to the homeowners

The system was designed and installed by Bruce Kell of Solaero Energy.  When he was going through the system with the new owners he commented that at a previous installation the natural gas utility had come and changed their meter because they thought it wasn’t working properly.  But it was – that’s just how energy efficient this system is.

Solar Power

A solar power system provides renewable electricity

A solar power system provides renewable electricity

The homeowners were very excited when the day came to commission the 2.3 kW grid-tied solar power system that will offset some of the home’s electrical usage with clean, renewable power.  The system can be expanded in the future, once they have lived in the home for a few months and have a clearer idea of how much power they will need.  The system qualified for a rebate on the upfront costs and Saskatchewan’s net metering program means that excess power produced over the summer months can be fed back to the electrical utility for credits on future bills.

enphasedisplay

Click here to see the Live Display for the Gardenview

The solar power system features a monitoring system that lets you see – live – exactly what each of your solar panels is producing at any time, as well as your overall production per day, per week, per month and since you installed the system.  The webpage will also show what this means in terms of the environment, showing the greenhouse gases offset by the system.

The solar panels and Enphase inverters have a 25 year warranty and an expected lifetime of over 35 years.

Owners’ Comments

The Gardenview has a bright, sunny kitchen

The Gardenview has a bright, sunny kitchen

After only a few days in their new home, the owners were already amazed by the solar heat coming through their south facing windows.

“The solar gain on sunny days is absolutely incredible – we turn down the fine-tune dial as far as possible in the morning and with opened windows in the afternoon, it’s still 24C on the main floor!”

Their in floor heating settings were tweaked to moderate the heat gain and heating costs have been very moderate for their first winter – under $300 for natural gas during the first year they lived in the home.

For more passive solar home designs see Suncatcher’s Solar Home Designs.  You can also buy a Study Set to have a more detailed look at the plans before deciding to purchase the full set of drawings.  Plans are priced at $995 for the Construction Drawings and $29.95 for the Study Set.