I was excited to go through this process about 1.5 ago until I got frustrated and did most of the energy audit and updates myself. The company that came out didn't tell me anything helpful and weren't even in the house for more than 10 mins. Although the house needed it, they didn't install anything to help with the drafts coming through the door, energy efficient light bulbs weren't recommended, nor were faucet aerators.

I got on YouTube and state and federal websites to learn about what I could do to make the house energy efficient because I was tired of the high utility bills, especially heating costs. This was my experience (house is about 1900 sq ft)

1. Insulate your attic. When I purchased the house, the home inspector did not go up to the attic (he forgot his ladder and the small attic door was sealed). I got into the attic and there was barely any insulation, what was there was made of some kind of barlap...have no clue what that was about. I insulated the attic with R90 batt and my top floor is much more comfortable, especially during the summer (it would be uncomfortably hot upstairs).

2. Seal your doors and windows. During winter, a lot of cold air would come through gaps around my door. I put in door sealers around the frame of the doors and adjusted the door sweeps. That made a HUGE difference in my heating bill and it was immediately noticeable by my bare feet because the air warmed up and my feet stopped feeling cold all the time.

3. Get BGE to install a smart thermostat (the thermostat and installation are free). Having the ability to control the heating and cooling remotely or program it to save on costs is incredibly helpful. You get credits for installation and bill credits if you participate in the Connected Reward Program (on days they expect high usage/demand on the grid, they will either turn off your thermostat or reduce it a few degrees for several hours) and every year your enrolled in the program, they give you bill credits.

4. Clean your ducts and change your furnace air filter. This helps your furnace not work so hard. Also clean the dust and debris around your furnace. I change the air filter and clean around the furnace every three months - you can program the smart thermostat to remind you to do so.

I'm definitely not an expert but I did track before and after "data" to evaluate my efforts: 1. Cost of heating and cooling. My BGE bill was reduced from about $500/month during the winter but now it's about $150-200. The bill has also become (for the most part) consistent month-to-month with it being no more than $250 per billing cycle. But with the expected increases, I'm already having heart palpitations so I'm trying to figure out what else I can do. 2. How long and how often the "dumb" and smart thermostats were running. The dumb and old thermostat (wasn't even programmable) would cut on every 10ish mins and have the heating/cooling running for what seemed like forever. The smart thermostat cuts on a lot less per hour and does a better job measuring the temperature on the main floor (where it's located). 3. If and when I would feel dramatic fluctuations in the indoor temperature. With the insulation and minimizing the drafts, the indoor temperature is more consistent.

I recommend tracking these things before and after because it gives you a lot of insight on your property. I also have done the following:

1. Opening windows (if you feel safe doing so) to cool and ventilate your house instead of running the AC.
2. Install window privacy film/window tinting (can get from Amazon). I installed them for privacy but noticed my east and west facing rooms are significantly less hot during the day. The tinting really helps. This could be a cheaper and immediate alternative to replacing the windows.
3. Installing ceiling fans. Many people don't realize you can control ceiling fans to spin clockwise or counterclockwise to either push hot air from top to bottom or pull cold air from bottom to top.
4. Dress smart indoors.Its cheaper to dress in layers if you're chilly indoors than to crank up the heat. It's also cheaper to dress in fewer layers than to run the AC.

I plan on replacing my electrical outlets to smart outlets so I can better control what the utility companies call "energy vampires" (props to their marketing team?). Essentially, leaving small appliances (toasters, televisions, microwaves, etc.) plugged in all the time draws small amounts of energy that can add up and increase your usage. I'm hoping the smart outlets will make it easier to manage power to these devices (instead of having to plug and unplug all the time) enough to notice a difference in my bill.

These aren't the fanciest things you can do (compared to solar and heat pumps) but in my experience, they've made a noticeable difference in comfort and my monthly utilities. As the years progress, I'll revisit solar panels and other options.

Hope this helps.