[tcfhgj]

> I do not fault the particular pump that we bought or our installers who were careful and professional. Apparently, however, we lack good rules of thumb to predict how a pump will perform in a particular installation.

A 278% estimation turning out as 150% real world performance, certainly was not done very carefully.

[spiderxxxx]

His efficiency data is tarnished by the leak. It was doing its best, but it was leaking, so it probably had to work harder to get the proper temperature. Also, he's comparing year over year - years have differences in weather. He's comparing one year's gas furnace use to 9 years of heat pump use - this is not a great comparison. Also, if he'd have had solar, or some other source of electricity, that was cleaner, say nuclear or solar or wind, it would be a lot less.

[NDizzle]

No, it works exactly like solar does. The companies say one thing, but reality doesn't match up. It doesn't matter how careful an installation is.

[tcfhgj]

Why not?

The real heating demand can be observed up front and with the typical (or even exact) weather you can easily determine the efficiency of the heat pump.

Yeah expect some inaccuracies, but not this huge

[NDizzle]

My weather person can't even predict what Thursday is going to do. You want accurate predictions for all of winter? That's why I mentioned solar. It's the same, but with sunlight.

[tcfhgj]

no predictions necessary, just check out the data from last year

[flankstaek]

Why do you think the manufacturers mislabeled efficiency has any relevance to how the installation team performed?

[tcfhgj]

I would assume the team knows the products they are installing

[falcolas]

Bad assumption. It’s like expecting framers to know the ins and outs of LVL production.

They’re there to put widget A in widget B, according to the instructions.

[olivierlacan]

That's a fairly inappropriate comparison in level of expertise necessary to design a system: LVL beams are picked by structural engineers, not by framers who generally install them where they're needed, based on a structural design which they have no say in because load calculations aren't a framer's job.

HVAC installers are not merely system assembly specialists, they're system design specialists as well in nearly all cases. Or at the very least they outsource HVAC system design to experts who are familiar with required air flow, static pressure, air changes, condensation formation and evacuation, and yes of course whether the system is appropriate for cold climates (cold climate heat pumps are notably different from temperate or hot climate ones: coils are larger to capture more heat from the air outside temperatures are very low); they have different refrigerant systems; and way more insulation to prevent the cold affecting operation; some even incorporate resistive heating elements... or a gas furnace in cases where their efficiency would drop below an acceptable threshold.

One of the biggest and most important part of an HVAC system design is sizing for climate and dwelling. It should be extremely suspicious to any installer that their design system efficiency would be so much higher than the real world system performs.

I'd be shocked if professional HVAC installers couldn't spit out several reasons why the system might be performing so poorly just by reading this blog post. Notably the absurd assertion that the installers were professionals despite wildly overpromising and underdelivering. Some contractors acting professionally doesn't make them professionals.

As others point out in this thread, implementing a system that meets the stated design goals roughly on target is what a professional does. I've seen some absurd lambasting of PV solar installs as an example of empty promises. Again, those are tell-tale signs of deficiencies, not an indictment of the underlying technology.

Which is the most irresponsible part of this senator's post. Given your post and prominence, the least you could do before publishing something like this is check your basic assumptions: that the installer did a fine job.

[falcolas]

As someone who recently had a heat pump installed, your expectations for minimum wage workers is rather unrealistic. We asked for one, they estimated the cost and installed it, and we paid the bill.

It was their second installation, ever. Red state with lots of gas installations and all that.

The onus of understanding that it wouldn’t work under a certain temperature, and would get lower in efficiency the lower the temperature, was on me.

It wasn’t that hard to understand, either.

[maxerickson]

The real world performance is with one of the units malfunctioning for weeks.