Is it feasible to retrofit solar electric on a house that's oriented east/west, not north/south?
We are thinking of buying an old house that needs a roof, furnace and hot water heater. As long as we have to replace the roof, I'd like to include solar electric, but the roof is oriented east and west, not south. The neighbor's house on the south side shades the lower half of "our" house. Would it be feasible to have solar panels or shingles on the side of the house on the upper portion that gets sun? Or on the roof, but raised and angled south? Or to add passive solar on the side of the house (sort of a trombe wall, but on the side of the house on the second floor)? Or . . . ?
It is possible to install photovoltaic panels on roofs that are oriented east west rather than south but not practical from an affordability and performance perspective.
I would offer that PV is a universally poor investment for residential consumers. Utility or government subsidies don’t make these systems any more affordable they simply shift the cost to the tax/rate payers thereby hiding the fact that they are a horrible investment, at this time.
- I think there is hope in the industry that at some point it can stand on its own merits but unfortunately we are nowhere near that point today.
- So you could prewire the house for future solar while you are renovating so if you live in the home long enough that it becomes affordable you’ll have the infrastructure in place.
South facing walls throughout the Midwest
If you are determined to have PV on your home you could add it to south facing awnings or mount it on a pole allowing panels (not shingles) to be oriented south rather than east/west.
In the mid 1970’s there was a huge push to install passive solar heating panels, encouraged by Federal rebates that often resulted in the inflation of the cost of the system. You can find these systems on the south-facing wall of homes throughout the Midwest.
- They basically operated on convections though some did have small fans to move air from the bottom of the panel over the solar heat exchanger and into the home through louvers in the top of the wall.
- Many are still in use most aren’t.
- Degradation to the panels resulted in discoloration and dysfunction.
Beauty is in the eye of the beholder so you’ll have to determine if curb appeal is impacted on homes with these types of systems.
Consider solar hot water
Solar hot water is a real possibility if you can configure the system to provide potable water and radiant heat.
A recent project in Michigan (www.brainright.com) has wall mounted solar water heating installed flat on the south side of the house. They knew they would lose some efficiency by not angling the installation but they wanted to prevent snow buildup.
- They have 2500 gallons of storage capacity that provides for all of their heating and potable hot water needs.
- The system works so well that they are literally looking for ways to dump the excess heat.
- In this case the system is actually too large for the needs of the home and occupants.
Get an energy audit first
Before considering any solar enhancements to the home you should hire a qualified energy auditor with a minimum of 10 years experience in residential energy audits.
A specialty in 100-year-old homes would be a real plus since the characteristics of the structure are significantly different than post WWII homes.
Reducing your energy load first will help make all other “energy” purchasing decisions more cost effective.
- This is especially important when replacing existing HVAC equipment.
- Otherwise you’ll purchase more efficient equipment but only manage to waste energy more efficiently.
For more information:
Read "I am building my home, and I wish to have solar installed now or in the future. What does solar orientation mean?" a Q&A answered by Florian Speier.