The existing subsidies are often specific to fossil fuels (heating oil and natural gas). You don't get them for installing electric heat pumps.
The better alternative would be to provide the subsidy in cash and let the poor decide what they need for themselves, instead of trying to choose for them between heating oil vs. investing in heat pumps vs. better insulation vs. turning down the thermostat and using the money for something else they need more.
You give them the money, and they'll spend it on blackjack and hookers. Regardless of whether you give them subsidy money, you have to charge higher prices for energy if you want any hope of reducing fossil fuel use.
> You give them the money, and they'll spend it on blackjack and hookers.
Stuff is fungible. If you give someone money for heating oil then they'll spend it on heating oil and use the money they would have spent on heating oil for blackjack and hookers if they want to. The only thing you're really doing is forcing them to buy heating oil instead of actual substitutes for burning more heating oil, like heat pumps or better insulation. Because one way or another they need to heat their living space, but if you satisfy that requirement for them in a specific way, it still frees up resources that they would have had to use for that and can now use for unrelated things like blackjack and hookers.
The better alternative would be to provide the subsidy in cash and let the poor decide what they need for themselves, instead of trying to choose for them between heating oil vs. investing in heat pumps vs. better insulation vs. turning down the thermostat and using the money for something else they need more.