Don't overlook state and local incentives too! Depending on where you live, you might qualify for additional rebates or credits beyond the federal tax credit. My state offers a $1000 rebate for heat pumps on top of the federal credit, and our local utility has an additional $500 rebate.

Based on all the helpful discussion here, it sounds like you should be able to claim the credit since you're living there as your primary residence and paying for the improvement. However, I'd strongly recommend getting this confirmed in writing before making such a large purchase. One thing I haven't seen mentioned is that you might want to consider having a written agreement with your in-laws about the improvements you're making. Since you're essentially investing in their property, it could be beneficial to document that you have permission to make these improvements and that you're responsible for the costs. This could help support your tax credit claim and also protect your investment in case your living situation changes. Also, since you mentioned you'll be there for 2-3 years, make sure you understand what happens if you move before the system pays for itself through energy savings. The tax credit helps upfront, but you want to make sure the overall financial arrangement makes sense for your timeline.

The Michigan Treasury is so behind rn its not even funny. Their still processing stuff from January smh

I feel your pain! Filed mine paper on Feb 5th and still waiting too. Called the Michigan Treasury helpline yesterday and they said they're running about 8-10 weeks behind on paper returns due to staffing issues. The automated system won't even show your return until they physically scan it into their system, which could be weeks from when they receive it. Hang in there - at least we'll get our refunds eventually!

You might want to consider submitting Form 911 (Taxpayer Advocate Service Application) if this is causing financial hardship or if your PCS timeline creates special circumstances. The Taxpayer Advocate can sometimes expedite processing when there are compelling reasons. The normal 20-week processing timeframe might be problematic with your military relocation timeline.

@Geoff Richards I completely understand your frustration as a military spouse! The processing times are definitely longer than they used to be. One thing that might help with your PCS timeline - if you're moving overseas or to a combat zone, you may qualify for extended filing deadlines which could give you more breathing room. Also, make sure you keep detailed records of your amended return submission since military families sometimes need to reference tax documents for security clearances or other military processes. Have you considered reaching out to the legal assistance office on base? They sometimes have contacts who can help navigate IRS issues for military families. Hang in there! 🇺🇸

Don't forget to check if you need to make estimated tax payments to California's Franchise Tax Board too! The FTB has their own payment system separate from the IRS called WebPay. Since you mentioned you're a California resident, you'll likely owe state taxes on that property sale as well. I made this mistake last year and only focused on the federal portion. Ended up with a penalty from California because I didn't make my estimated payment on time. The California tax on my property sale wasn't small either!

I went through almost the exact same situation two years ago when I sold my investment property and had to handle everything while backpacking through Southeast Asia. Here's what worked for me: First, definitely set up your electronic payment BEFORE you leave. I used IRS Direct Pay and it was seamless - no enrollment required and you can schedule the payment in advance. With $95k, you'll want to double-check the daily/monthly limits on your Bank of America account for ACH transfers. Second, consider making your payment in installments if cash flow is tight. The IRS allows you to set up payment plans online, and the fees are pretty reasonable compared to the stress of coming up with the full amount at once. Most importantly - and I can't stress this enough - file for the extension if you haven't already, even though CA residents get the automatic October extension. Having that official extension on file gives you extra protection if anything goes wrong. One last tip: Download the IRS2Go mobile app before you leave. You can check the status of your return and payments from anywhere, which gave me huge peace of mind while I was dealing with spotty WiFi in rural Thailand. Safe travels and don't let tax stress ruin your trip! You've got plenty of time to get this sorted before you leave.

One thing nobody's mentioned yet - if you're paying a large amount, check your credit card limits before trying to use Pay1040! I tried to pay my $14,000 tax bill with my credit card (wanted those sweet travel points) but got declined because it exceeded my single transaction limit, even though my overall credit limit was higher. Had to call my credit card company to get temporary approval for the large transaction. Also, calculate the processing fee before deciding - on larger amounts, the 1.87% can add up quickly.

For what it's worth, I've used both EFTPS and Pay1040 multiple times. EFTPS is better for planned payments (like quarterly estimated taxes) since you can schedule them in advance. Pay1040 is better for last-minute payments when you need it to process immediately. If you plan to make any future tax payments (like if you're self-employed), it's worth registering for EFTPS now anyway, even if you use Pay1040 for your current payment. That way you'll be all set up for next time without the waiting period.