Nice windows cost too much?

Nice windows cost too much? Maybe.

One clarification. By “nice” I mean like, REALLY REALLY nice. From a energy standpoint. (and comfort, which is similar, though not totally the same… since a window that let’s in more heat from the sun but might have lower R value can be less comfortable to sit next to than a higher-R value window at night).

Our windows are already really good. R-5. Triple pane. Insulated frames. Warm edge spacer. But there are even better ones. Would it have made sense to pay a lot more (like $5000 or more) to use fancier windows?

I should dig up the invoice/estimate for windows from the contractor and window manufacturers, but let’s just say the differential was $5k between our very nice “Preminum Paradigm double hungs” made in Maine, and some Canadian fiberglass or German passivhaus-certified windows.

Also note… already with our VERY GOOD windows, our heating bill is already only in the range of $500/year (pre-PV offset). VERY LOW. Thanks to good insulation and sealing throughout the house.

So what could one do with $5k instead?

1. Buy 1/2 a Prius third-party plug-in system from A123. That would take your carbon use WAY down. In $$ let’s say you go from 50MPG to 100MPG (effective) and drive 20 miles roundtrip 50 weeks a year. That’s

Normal Prius (assume 50mpg)
20mi/50MPG * 5days * 50weeks * $4/gallon = $400 per year

“100 mile” EV-mode Plug-in modified Prius:
$200 per year saved!

Whoops! I’ve wrong! $200 is not much. Of course, if you drive more, it could be a good way to spend the $. But remember, $5k gets you only about 1/2 way there since I think those extra batteries cost at least $10k. More I think.
It’s like turning a $20k Prius into a $30k LEAF I guess. Plus, remember, the car is not going to last 30 years like the PVs!

2. Add “solar siding” or a small low-mass sunspace to your house. That would get rid of maybe $250 per year. So 20 year payoff.

3. Pay for 1/2 a solar hot water system? Eh. Also a VERY LOW payoff. We only spend $300 (maybe?) on hot water. And solar would only add 50% solar fraction, so $150 savings per year for $9000 spent?

4. Buy some more PVs. Let’s assume $6/peak watt. With roughly 30% tax credit and $1/watt discount from your utility. So that’s actually $3/watt. So $5000 could buy you 1600 watts, which in Massachusetts/New England you can safely multiple by 1.2 to see what you’d produce in KWh for a year (an empirical rule-of-thumb). So that’s 2000 KWh per year.

So… assuming you have net-metering (which most people in MA do) and assuming $0.20/KWh, then that’s… $400 saved per year.

And since windows and PV systems probably have similar 30-year lifetimes, seems like PVs are a better deal too.

Plus I think my $5000 difference is low. Anyway, you get the idea.

My point is… even if money is made on trees for you. You might do better to put PV arrays on all your neighbors houses or something rather than worry about your already very good windows too much.


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