Peco, my electricity supplier, has an offer I could easily refuse: Buy the same amount of power I’m getting now, but pay more for it.

At my house, this $7.62-a-month premium would boost the power bill about 4 percent – enough to cover the extra monthly cost of 300 kilowatt hours of electricity from the 43 wind generators at a Pennsylvania wind farm, enough to provide a third of the electricity we use.

I like the idea of environmentally friendly wind power, so maybe I’ll kick in the price of a sandwich to help this technology spread.

If that’s not the best hard-nosed business decision, so what? It’s my money.

But what about when the stakes are bigger, like when your investments for retirement or college are on the line?

There are nearly 120 “socially responsible investment” (SRI) mutual funds that limit their holdings to stocks in companies that meet some moral or social test, according to Morningstar, the investment-tracking firm. Many funds, for example, avoid companies that produce weapons or products containing alcohol or tobacco; others require policies friendly to workers or the environment, or to suit Catholics, Muslims or other groups.

Traditionalists argue that investing is only about maximizing financial returns, and that other considerations ultimately undermine that goal.

However, the data is mixed. Since the beginning of the year, the SRI funds have performed about the same as they have for the most recent one-, three- and five-year periods: They’ve been beaten by about 54 percent of ordinary mutual funds.

That middle-of-the-road result masks a lot of variation, so investors attracted to SRI funds can figure the tradeoffs only by looking at funds one at a time, says Annette Larson, a Morningstar spokeswoman.

Morningstar data, at www.morningstar.com, compares individual funds with their category averages. For a free list of SRI funds, go to www.socialfunds.com.

Personally, I wouldn’t invest in a proven dog no matter what the social issue. But when the call is closer, it seems to me the key question is not whether an SRI fund will give the biggest returns possible; it’s whether the returns will be enough to achieve your financial goals. If they will, then a small sacrifice for making the world better in return may be a fair exchange.

At $7.62, it may be a bargain.