This is a prototype I'm working on, and would love feedback - send any thoughts/comments/suggestions for improvement to tophatmonkey@gmail.com

This page is made to help you figure out heat pumps. Heat pumps used to have universally terrible performance when it got below 40 degrees, but in recent years, that's changed - some now work well down to -22! But that's not true for all heat pumps, which is why I made this tool to use the actual performance metrics to estimate how each would behave with your house, in your specific location and your weather.

How?

First, use the map to choose where your house is.
Using that, we get the hourly weather for your location for the full year.
Then, use the text boxes to describe your house - where is it, how big it is, how well insulated, and how much your electricity costs.
Using that, we make a model of your house and estimate heat loss for every hour.
Using those together, along with capacity/efficiency data at different temps for lots of heat pumps, we estimate how much electricity each one would use, and figure out which ones won't be able to keep up - look for "Hours Over Capacity" to see which heat pumps aren't quite keeping up. A little of that is OK, a lot, not so much.
The page combines the purchase price with the electricity usage price, extrapolated over x years (default 15) to figure out an all-in cost. A more efficient heat pump might cost more upfront, but if you need a lot of heating or cooling, it might end up being cheaper overall. We sort by that total price.

This page may look kind of crappy, but don't judge this book by its cover! It's more sophisticated than most pages that look a lot nicer.

Where's your house?

Heat pumps get less efficient in more extreme temperatures, so to estimate energy usage, we find your nearest weather stations and get the hourly weather for the past year.

Latitude, Longitude

How warm/cold do you keep it?

The bigger the temperature difference between inside and out, the faster your walls let heat through, out in the winter, in in the summer.

F Heating Setpoint
F Cooling Setpoint
F Building Balance Point Offset - This depends on insulation, insolation, and waste heat from other energy use, so probably want to redo, but basically this sets how much colder it can be outside before the building needs any intentional heating
Total Heating Degree Days
Total Cooling Degree Days
Over days last year

How big is your house?

Square Feet

layout

How well is your house insulated?

R- Average Insulation

How expensive is your electricity?

/kWh

How long do you think a heatpump will last?

Years Heatpump Operation

Based on all that.... Your Heat Pump Options!

Name	Brand	Refrigerant	Performance	Operation

Debug

Heat pumps are pretty awesome. They're basically air conditioners that can run in either direction, and because they move heat between in and outside instead of just creating it, they can be more than 100% efficient! In many cases, they're in the range of 400% efficient, or even more. You can get more heat in your house using natural gas to generate electricity to run a heat pump than if you burn the gas directly in your house. Crazy!

This tool is for people who are interested in buying a heat pump without going through a contractor, or for any contractors who might find comparisons useful. In many cases, especially with minisplits, it's not too hard to do it yourself, and much cheaper than hiring a professional. But they can be a bit tricky to compare when it comes to efficiency versus cost tradeoffs, which is why I built this tool to help you play around the numbers and figure out what might be right for you.

If you decide to DIY this, though, I'd advise a few things. First, watch a bunch of YouTube DIY videos, but be aware that it's not quite as simple to do a good job of it as they show. If you get one of the MrCool DIY series pumps, you can just use their pre-evacuated linesets, and I've heard that's pretty simple. But if you go with one of the others with normal linesets, you need a vacuum pump, torque wrench, and the other tools they recommend, but you also need a digital micrometer, a flaring tool, and you probably want a coring tool with shutoff valve, and you might want to do a pressure test with nitrogen, which means you probably need a pressure regulator. You probably also want a higher quality vacuum pump than most YouTubers show. Many YouTubers use an analog manifold, but for pulling a deep vacuum and making sure it holds, that's like trying to measure inches with your car's odometer - the level to which you need to measure is invisible on that scale. Instead, you want a digital micrometer. This isn't to scare you off, I did my own this way and it wasn't hard once I figured out what I needed, this is just to make it so you don't get halfway into your project before you realize the real cost of doing this right.