Solar Power for Houses: Your Residential Solar Power System

Passive solar heating is a great way to provide much of your home’s heating for free. Almost every home gets some solar energy coming through the windows, but there is a vast difference between the average house and a home heated with passive solar energy.

Building a new house that is passively solar heated is not significantly more expensive than building a normal house. This makes passive solar the most cost-effective form of solar power for the new home. Every new home should be built using passive solar techniques because home heating and cooling needs can be reduced greatly – potentially to zero in certain circumstances.

All this sounds wonderful, but there is one caveat: you must find a good architect who understands passive solar design. Some architects do not understand how to do it properly and mistakes made during the building process may prove costly later.

Passive solar heating covers a wide range of strategies, including passive solar thermal hot water heaters such as the batch and thermosyphon, but it’s usually used to describe heating the house air and structure.

Direct Passive Solar Heating

The simplest form is direct passive solar heating. This involves big windows on the south side of the house. The sunlight falls onto a dark surface with a high heat storage capacity such as a masonry floor or wall painted a dark color. Water is sometimes used instead – this involves water contained in glass or transparent plastic. It has slightly different properties than solid walls, but the basic idea is the same. The wall or floor absorbs energy on sunny days, and releases it at night or on cloudy days when things get cooler.

Of course, you don’t want the house to overheat in the summer. This is generally avoided by building overhangs over the windows. In the winter the sun is at a low angle and comes in the window. In the summer, especially near midday, the sun strikes the overhang and doesn’t come into the room. This leaves the room much cooler.

Trombe Walls (Indirect Gain) and Solar Spaces (Isolated Gain)

There are two other major passive solar heating strategies, Indirect Gain and Isolated Gain. The most common Indirect Gain method is the Trombe Wall, and the most common Isolated Gain method is the solar space.

Trombe walls involve a thick wall painted a dark colour. An inch or so in front of it is glass. Sunlight enters through the glass and is absorbed as heat by the wall. The glass helps prevent heat loss, and wall slowly releases the heat into the rest of the house. Again, a Trombe wall is placed on the south side of the house.

A solar space is basically a glassed-in space on the south side of the house. They are also sometimes known as solar rooms or solaria. Solar spaces can act as greenhouses, and they are sometimes referred to as greenhouses. However, they are not the same as greenhouses designed to grow plants.

The glass is vertical, and there usually isn’t glass overhead. This is so that the glass can be shaded in the summer to avoid overheating. It also means the plants that grow there have less light than they would in a true greenhouse, although more than they would in your house. Since they are attached to the house, you may not want to grow large numbers of plants in it if you’re allergic to mildew. However, if you’ve always wanted a greenhouse,why not use it to grow plants?

These three types of passive solar heating are the most commonly used. While the systems describes here are simple and this overview is simple, there’s a lot more to passive solar design when you really start looking deeply into the subject.

Sources:

Arizona Solar Center

US department of energy: energy efficiency and renewable energy. Passive solar home design.

The less power you use, the less expensive the home solar system you will need to power your home.   Increasing energy efficiency is a great way to do this.   Recent appliances are more energy-efficient than older ones but the extent of the energy savings varies greatly between different types of appliances.  The two most energy-intensive appliances in most homes are refrigerators and dryers.

Why You Need an Energy Efficient Refrigerator

Refrigerators use a lot of energy.  New refrigerators use a lot less energy than older refrigerators.  There is also a great difference in energy use between different refrigerators.  The standard advice is to buy a new energy efficient refrigerator if your current fridge is more than 10 years old, as the energy savings will pay for the new refrigerator.

New Energy Star refrigerators use 50% less electricity than the average ten year old refrigerator.   If you live in BC, BC Hydro runs a fridge buy-back program in an effort to reduce electricity use. EnergyStar is a program that certifies energy efficient appliances.   If you live in BC Canada, BC hydro has rebates for buying EnergyStar appliances.   Many other areas probably have similar programs.

Well-maintained appliances are more efficient than poorly maintained ones, as well as doing their jobs better.   If you cannot afford to replace an aging appliance, performing regular maintenance will help minimize its its electricity use.  This will not reduce electricity use to the level of a new appliance, but it will reduce it greatly over a poorly maintained one.

Energy Efficient Dryer or Clothesline?

Dryers use a lot of energy, sometimes as much as the refrigerator despite the fact that they aren’t on all the time. Ideally, one would hang clothes to dry outside, thus using no electricity at all, but in many places this is inconvenient in the winter. Clothes will dry in the cold, but not if it is raining on them.

Drying outside is against bylaws and home owner association regulations in some places. Do be aware that many of these regulations are being challenged and declared illegal, so if you want to dry outside you may be able to do so even if you weren’t a year ago. The movement to make anti-drying regulations illegal is often referred to as the ‘right to dry’ movement, and it is widespread.

Indoor drying racks also work, but do take space while the clothes are drying.  The most inventive indoor drying rack I’ve seen was hung from the ceiling of a kitchen and hauled up and down with a rope and pulley system.  This made extremely efficient use of space and allowed a washer’s worth of clothes to be dried indoors in Britain in the winter.  It worked well enough that the house did not have a dryer.  If you have a small household that does not produce huge amount of laundry this system could well work for you.  It is it is hard to get more electricity efficient than this!

If you do want a dryer, an energy-efficient dryer will save on electricity, although not as much as letting half of each load air-dry.

Energy Efficient Clothes Washers

Front loading washers are more efficient than top loading washers.  If you don’t have large amounts of laundry, a compact washer will save you electricity.  If you do have large amounts of laundry, a full size front loader may be your best bet, as doing one larger wash takes less energy than doing multiple smaller washes.  Some dryers are more efficient than others, so pick an efficient one.

Energy-Efficient Dishwasher or Handwashing?

An energy-efficient dishwasher that is fully loaded uses less hot water than hand washing.  However, this requires that you load it fully.  If you only ever wash small loads at once, hand washing may be more efficient.

There are also energy efficiency improvements to be found with cooking appliances, but they really deserve an article of their own.

Increasing energy conservation and energy efficiency are the most cost effective ways to reduce the amount of money you pay for energy.  Before you invest in alternative energy sources, you should check that your house uses as little energy as possible while still allowing you the lifestyle you want.   Of the two approaches, the simpler is energy conservation.

Energy conservation involves using less energy by doing things like turning off the lights when we’re not in the room.  There is no upfront cost to such actions, although they do typically require behavior changes.

Ways to reduce your power use through energy conservation

• Turn all lights out when you leave the room
• Set your computer to fall into hibernation mode when it is not in use
• Unplug appliances when not in use, or get a power bar and turn the power bar off at night
• Buy a timer for your home’s thermostat so that your home will be warm when you’re home and moving about and cooler at night and when you’re at work
• Turn your home’s thermostat down a couple of degrees Celsius and wear a sweater – presuming your home is not leaky enough that you’re wearing a sweater anyway and freezing cold besides
• Turn the TV off if you’re not watching it

Basically, if you aren’t using it, it shouldn’t be on.

Energy efficiency involves using appliances that can do the same amount of work with less energy.  It does not involve you changing your daily behaviour.  The classic example is replacing incandescent lighting with compact fluorescent, but it goes far beyond this.  The largest use of electricity in many homes is heating.  By insulating the house, the amount of energy required to heat the house is reduced.

Cheap ways to reduce your power use through energy efficiency

• Replace incandescent bulbs with compact fluorescents
• Insulate your hot water heater
• Insulate your hot water pipes
• put plastic film over windows during winter

More expensive, but very useful

• Buy an energy-efficient refrigerator if your current fridge is more than 10 years old
• Insulate your ceilings, walls and floors
• Replace single-glazed windows with double or triple glazed windows

Of course, if you really want to increase energy efficiency there are a variety of methods for passive solar heating, but that is beyond the scope of this article.

When you install that new appliance…

I once lived in an apartment where the landlord had replaced all the windows with new windows that were supposed to be much better insulated and lose less heat.   However, he had installed them badly and there were gaps between the windows and the frame.  One of the gaps was so large you could see right through it to the outside.   Because of this, the house would not stay warm despite the new windows and the landlord complained about his energy bills to us.  Meanwhile, we complained that we were always cold.

This shows the importance of installing new energy efficient objects correctly.  If installed incorrectly, the object may well work badly if it works at all, and you may have done a lot of work and spent a lot of money for no energy savings.  So do it right the first time!