Look into an energy audit to pinpoint what needs to be done first. You might qualify for financial assistance. Check with your local electric utility.

Start from the top down. If you need a new roof, a new roof 1st. If you need foundation work, then that should be done. Anything regarding safety, should be your next priority, like electrical, and plumbing. Then HVAC and air sealing. . Always the house itself, before you do anything pretty.

Speaking only from an energy efficiency standpoint, get an energy audit, either through your utility company or with an independent inspector. That will help you to prioritize.

In a typical older house the priority would be 1) air sealing, 2) adding insulation to attic, 3) adding insulation elsewhere, 4) replacing seriously outdated HVAC equipment (probably with a heat pump), 5) windows/doors, 6) a deep energy retrofit to net zero standards. Add solar power if your site is appropriate along the way.

If you choose to go with significant sealing/insulation upgrades you may well need a much smaller HVAC system as well as mechanical air exchange with heat recovery. A blower door test will tell you if you need the latter.

In a well built house upgrades to insulaion and air sealing will continue to pay back for the next hundred years or more, so set your roi calculations appropriately, knowing that you may not personally accrue all of the return, eg pay it forward.

Great advice so far. Do your research on windows. If your home still has the original windows, look into restoration + storms before replacing.

Top down, bottom up. Take care of the things that hold the house up and keep the water out. The head and the feet. Once you can breathe, then analyze the arteries. The plumbing and electrical. You do not want to bury old crumbling infrastructure under insulation. It' too hard to tackle after insulating. Air sealing and insulating come next. Then, you can tackle the cosmetics that most people want to tackle first.

You can put storm windows over the original windows. Curtains with linings, particularly well-fitting Roman blinds can provide a lot of window insulation (obviously mostly at night).

An energy audit is good, but you can DIY. There are websites out there that will give you a rough calculation. Measure the insulation in the attic, if you can't figure out if there's insulation in the walls, find an inconspicuous place to look (like in a closet). What you want is a list of what the issues are and what the options are to fix them. Hopefully, the biggest bang for your buck and simple, easy projects that help will pop out.

Echoing the energy audit rec--one of the things that they give you in the report is a recommended order of improvements. We live in a mild climate, for instance, so they told us we wouldn't get much bang for the buck insulating our exterior walls relative to other improvements--but if you live somewhere cold or hot that could be huge to do. I also found it helpful to make a multi-year plan. Are you planning other renovations where it would make sense to integrate some energy improvements? Can you stagger improvements to take advantage of the new tax credits (which have annual maxes)? Which things can be done incrementally vs. which make more sense to do all at once?

You live there; so live well.

Of a million things to do, we put in a master closet first. Why? Because we had no place to put our clothes.

For other areas, we figured out where we spent the mist time and focused on them. For instance, our bedroom, the living room, our bathroom…but the dining room… an hour spent there a day? That can wait.

You will get there, its all overwhelming at first but then you look back and you-see how far you have come, and its not so distressing.

No one has ever been arrested by the Not Done Enough To An Old House Police, so dont forget to just enjoy your old house in the qwirky ways that it has.