Adapted from The Complete Idiot's Guide to Renewable Energy for Your Home (Alpha)
Because solar thermal heating systems are so flexible, both in type and design, there is definitely one that will work for you. You might decide to take advantage of natural sunlight by adding a sunroom, greenhouse, or new shed to your property. Alternatively, you might incorporate solar thermal elements into a new home or shift some of your heat load away from an existing boiler or furnace, without making any major renovations.
Measuring Your Solar Heat Potential
If you want to get really technical, you can visit the National Renewable Energy Laboratory's site and find the 30-year averages for "monthly solar radiation and illuminance" for the nearest city in your state – if you enjoy sifting through large amounts of raw data, that is. While you may assume that you're not a good candidate for solar because you don't live in a traditionally sunny climate (Arizona, say, or Florida), nothing could be further from the truth. It's those living in colder climates with rising heating bills in the winter that have the most to gain by installing a solar heating system. While you won't be getting all of your heating needs met by rooftop collectors or a passive solar design such as a sunroom, you can cut the energy used for heating your home and water by nearly half or more (and chop your bills down in the process).
Depending on how particularly cold your property becomes, a solar air collector may be preferable to a liquid system. It's true that air is not as efficient as liquid for transferring heat, but air is also not susceptible to freezing. What's more, an air collector may be a better fit for your home aesthetically. These collectors weigh less than their liquid counterparts and can be integrated into walls or roofs so that they are less obtrusive. When the solar air collector is not heating the room into which it's being directed, its heat can be diverted for heating your home's stored water.
Air systems will tie in well with a forced-air distribution system, while liquid systems, which circulate water or an antifreeze solution, can be plugged in to almost any system, including radiant systems and boilers with radiators.
Active systems (systems using fans and pipes to circulate heat) make the most sense economically when you plan to use them year round, or almost year round. In other words, they are best for places where you get plenty of cold temperatures and decent sunlight. On the other hand, passive designs – the use of sunrooms, sunspaces, and other building elements – offer the beauty of simplicity and dependable long life. And designing your home to best capture sunlight makes great sense when building new. After all, with no moving parts and with sturdy materials such as glass and concrete, there's little to wear out with a passive system.
Passive systems are a little more labor-intensive, however, since you may need to open and close vents or shades manually each day, but these tasks are not overly time consuming. You may even find that you enjoy being a little more in touch with the daily cycles of the sun and the free heat it's providing. What's more, solar heat is generally more comfortable than the forced-air type you're likely used to, which can aggravate allergies as it blows around and feel stifling as it ratchets the heat up too high.
The same charting system is used to determine your site's solar potential whether you are looking to install solar heating or solar electricity – and either reading can be done by a certified installer or with your own handheld reader called the Solar Pathfinder. There's more to your solar picture than the just the level of shade-free light that's hitting a particular part of your property. There's also the sunlight's intensity – that is, when the sun is strongest. Sun (not surprisingly) is more intense in the summer months and when it's not being blocked by trees, hills, or fog and clouds.
Improving the Situation
If your house is already built, your options for where to put your solar collectors (in the case of an active system) are more limited. You"ll usually want to use your existing roof as a place to site the collectors, as close to south-facing as possible. You want to avoid shade – or the possibility of future shade through growing trees – and to choose an open spot that gets optimum sunlight during daytime hours. Dealers sell the collectors in many different configurations. For example, you might buy four solar collectors equaling 40 square feet and laid out side by side or stacked, depending on your design needs. Also, an array of colors are available for framing the collectors so that they match your existing home.If you are in the market for a new shed or workroom or plan to add a garage or other structure to your property, you"ll have more flexibility in positioning this new building for optimal solar heat collection. This will also open up space on your home for installing solar PV panels on the main house, should you choose to go that route now or if you want to leave that option open for the future.
A passive solar heat system can be an add-on, too – perhaps you're in the market for a sunroom, or have an existing deck that you'd like to incorporate into the home. The real possibility for this kind of addition will depend on your home's current orientation; whether it is already situated with south-facing windows, a patio, or a deck; or the degree to which you're willing to renovate.
An open floor plan is a particularly good fit with passive solar heat, especially if you're living in a warm and humid climate, so you may want to consider removing interior walls to open up space as part of a remodel. For areas with colder climates, keeping separate "zones" in the home can enable you to heat only what you need to heat and thus achieving better energy efficiency during day-to-day use.
BRITA BELLI is editor of E and author of The Complete Idiot's Guide to Renewable Energy for Your Home.