Solar Panels, Part 1

This year we decided to get solar panels on our house for a variety of reasons, the main one being that our roof is nearing the end of its lifetime. I thought I’d write up my research so that it might help others.

The best approach to decarbonizing is to use less energy in the first place. Since we bought our house we’ve installed more efficient appliances as the old ones died, most significantly a much more efficient HVAC system for the house. The last time PECO came out to do an energy audit, they installed a lower flow shower head and said that our main energy usage was our old water heater, which was also nearing its end. I was skeptical, but replacing the water heater with a more efficient heat pump hybrid system cut more than 1/3 of our energy bill in the spring/fall. A side benefit, heat pump water heaters act as dehumidifiers and help keep our basement drier.

Further efficiencies at this point would require exorbitant expenditure or changes in behavior (thermostat at 80?), so the next step is solar panels. But we wanted to do the roof first, as I’m told that if you need to redo the roof after the solar panels are installed, it can cost anywhere from hundreds to over a thousand dollars for an electrician to come out, unhook the panels, remove them, then put them back and reconnect them.

Roofers are apparently in high demand now and of the 6 we called, we eventually were able to get quotes from three – two of them recommended by one of the solar companies. The local favorite, Walker, did not respond to our multiple attempts to reach them unfortunately. We received two quotes at about the price we’d expected (the third was about 50% higher – always get multiple quotes!). We decided to go with a local company, Scheinfield, who was the only one of the three that asked us what kind of roofing tiles we wanted. Other roofers seem to have a single brand they work with. Owens and Certainteed seem to be the main tiles available here, although there are a few other major manufacturers. Owens is preferred by Consumer Reports, but most other sources I found cited little difference in quality. We decided to go with the slightly heavier and more expensive Certainteed Landmark Pro tiles, as the cost was not substantially more (about 10%).

The solar companies we talked to do not coordinate with the roofing companies. The roof gets done first, then the solar companies cut whatever holes they need to install the panels afterwards.

We got quotes from four solar companies recommended by people we know (and from my work on the EAC):

Each uses a different type of panel, but all produced roughly the same amount of energy – and all are from reliable solar panel manufacturers. The estimated break even time is about 10 years for each of these systems with an expected lifespan of 25 years. We’ll initially pay the full cost for the system. When we do our taxes next year, we get a 26% tax credit from the federal government, which is set to expire after next year. In addition, of course, we save on electricity as our panels will cover most of our usage except in winter and PECO allows for net metering, where we get paid for excess production. Not all energy provider options here allow net metering – most don’t. We’ll actually have to change from our clean energy provider back to PECO for net metering. Finally, we’ll produce SRECs (solar renewable energy credits). The price for these varies by state, and here in PA they are in low demand because the state has set a very low requirement for how much clean energy utilities have to purchase. Estimates were that our system would produce ~$200/year of SRECs, which is small compared to the electricity savings. One last note, solar panels age, its important to look at what they’re warranted for as the manufacturers specify the expected power after 25 years. It should be in the 92%+ range, but know that you will get slightly less power out of the panels as they age.

Open Sky is local and uses Hanwha solar panels, they were the fastest to get back to us. But the price was not competitive. Power Stream uses LG panels and batteries (more about batteries later), but was also not price competitive. TerraSol uses Sunpower panels, which are the most efficient of the panels we looked at. They would cover less of the roof than most of the other systems, if density matters to you. TerraSol and Sunpower both have long track records, the price was very good and its a local, family owned business. If we only wanted solar panels, we’d likely have gone with TerraSol. But Sunpower’s battery technology is far behind others and the battery price was double for an inferior system.

We decided to go with Solarize DelCo’s Lumina Solar. Solarize DelCo is a non-profit chapter of a larger Solarize organization that’s trying to make solar power easier to install. Usually Solarize works by getting a group of homeowners together and then negotiating a group price. In DelCo’s case though, they’ve just negotiated pricing with a company – Lumina Solar – who doesn’t seem to have worked with Solarize groups before. Lumina Solar uses REC solar panels, which are slightly less efficient than Sunpower’s but the price per Watt generated is almost exactly the same. Lumina Solar’s advantage is that they install Tesla Powerwall batteries. Lumina Solar’s biggest downside is that they are not local and are a new company – 3 years old – with little track record.

A word on batteries. From an environmental or financial perspective, batteries are not a great idea in suburbia where power hookups to the grid are straightforward. The price is high, on the order of $10,000 for a battery that can’t power your house for a whole 24 hour period (even a Garden City sized on like ours). But, without a battery system, solar panels cannot power your house at all. If the power goes out, you’re in the dark like everyone else. With solar panels and a battery, you can operate parts of your house indefinitely if you’re careful with what you use (no air conditioning!). Also, under current law if you install the battery with the solar panels, the 26% tax credit applies to the whole system including the battery. We were told if you add the battery later, the tax credit does not currently apply. Our investment in a battery is largely because I expect America’s dysfunctional politics to continue to hamper its ability to handle the oncoming climate crises and protect its citizens (see the power crises in Texas or drought out west).

The other option that both Terra Sol and Lumina Solar offered were critter guards. These are metal meshes designed to keep animals from getting underneath the panels and nibbling on wires or building nests. Neither seemed to think it was necessary but both were willing to install them for between $1000-1500. For mounting Terra Sol used traditional metal flashing while Lumina Solar uses RT-Mini II flexible flashing. The consensus I could find online was that there’s little difference between the technologies at this point. Both systems also use micro-inverters, where each panel has its own inverter to convert the panel’s DC to the grid’s AC rather than a large central inverter. This seems to be becoming increasingly common, and seems like a good idea because if one micro-inverter dies, you’re only down one panel whereas if you have a central one and it breaks you’re out of luck. Historically I think larger, centralized inverters were more efficient, but that is no longer the case. One other difference in the systems we looked at is that Sunpower makes everything – the mounting, the inverters, the panels all come from a single company whereas the parts of other systems are sourced from several manufacturers.

Next step will be to work out the final details. Roofing and electrical permits are needed from the township, which I expect will run in the $100-150 range. There is some damage to the plywood beneath the roof that will have to be replaced, and most roofers charge extra for that (and plywood prices are currently rising). I’m still not clear on how the battery will be wired up, because ideally we don’t want the larger house systems (HVAC, water heater, washer/dryer) run off the battery circuit. I’ll update with part 2 once everything is installed hopefully by the end of the summer.

Categories: Ramblings