Although they may not be a direct subsidy of solar power systems, tax – deductible home equity loans are akin to a government subsidy. If you take out a second mortgage to pay for your solar equipment, the government lets you deduct the interest on that loan from your taxes. So if you’re making a monthly payment of, say, $300 for a second mortgage, your net cost may be only $200. The tax-deductible home equity loan works exactly like a subsidy, but it’s called something else. See Chapter 22 for more details on financing.