Mitsubishi Electric Diamond Contractor | Seattle & Eastside
Diamond Contractor Installation, Service and Warranty Registration
Mitsubishi Electric Diamond Contractor in Seattle & the Eastside
NW Mechanical is a Mitsubishi Electric Diamond Contractor. Mitsubishi awards that designation, and it changes two practical things: who's allowed to install the equipment under full warranty, and how long that warranty runs. There are also two limited offers running this fall, which we've set out below.
Authorized Diamond Contractor
We install, service and warranty-register Mitsubishi Electric systems across Seattle and the Eastside. Family owned, and we've been working here since 1977.
MITSUBISHI
Diamond Contractor
PUGET SOUND ENERGY
Recommended Energy Professional
WASHINGTON STATE
Licensed, bonded and insured
LOCALLY OWNED
Serving the region since 1977
Offers running now
Two Mitsubishi programs are open at the moment, both on qualifying residential installations.
Fall Rebate, through November 25. $750 off the installed price of a qualifying Mitsubishi multi-zone system. On some models, adding a branch box takes that to between $1,050 and $1,450.
The equipment has to be R454B, so the older R410A models don't qualify, and it's for homeowners rather than builder, contractor or commercial work. The rebate window closes November 25, 2026, and the system needs to be installed and claimed by December 31.
Diamond Advantage, through December 31. Running October 1 to December 31, 2026, this one bundles three things into a single purchase on qualifying residential M-Series and P-Series systems. Once it ends, the bundle goes with it. The Diamond Contractor warranty terms underneath it don't change.
12-year parts
Parts and compressor warranty on a single-family installation, as long as the system gets registered with Mitsubishi in time.
12-year labor
Extended labor coverage at no cost, through JB Warranty. Most warranties cover the part and leave you paying for the hours.
12-year financing
Through Synchrony, set up as one monthly payment instead of separate equipment, installation and warranty costs. Subject to credit approval.
Both run through participating Diamond Contractors, on accepted proposals that meet the program requirements. We'll tell you which one fits your project, and whether it qualifies, before you commit to anything.
What Diamond Contractor status actually changes
Mitsubishi runs Diamond Contractor as a multi-stage qualification that keeps installers current on the equipment and on how it gets installed. What shows up on your invoice is the warranty.
| Parts warranty | 12 years on a system installed in a single-family home by a Diamond Contractor |
|---|---|
| Compressor warranty | 12 years, same conditions |
| Registration deadline | Within 90 days of installation, or the 12-year term doesn't apply |
| Who registers it | We do, as part of the job, and we pass you the confirmation |
| Labor coverage | Not part of the standard warranty. It's what the Diamond Advantage bundle above adds. |
The 90-day registration window matters. A system can be installed perfectly and still lose the 12-year term if nobody registers it. We do it as part of the job, so it isn't left sitting on your list.
Why Mitsubishi comes up so often in this region
Mostly it comes down to the housing stock.
A lot of the housing inside Seattle went up before residential cooling was a thing, and plenty of it has no ductwork at all. That's the biggest constraint on retrofitting comfort into an older house here, and it's why ductless comes up in so many of our conversations. Mitsubishi's M-Series is built for that situation: heating and cooling room by room, without running duct through finished plaster in a house from the 1920s.
On a bigger property, or a light commercial space, the P-Series does the same job at higher capacity. And if your house already has ductwork in good shape, a ducted heat pump is often the better call. We'll say so if that's what we find.
Ductless and mini split systems
The usual route for a house with no ducts, a converted garage, a bonus room or a finished lower level. One head per zone.
Heat pump installation
Where the ducts are already there and in good order, converting to a ducted heat pump adds cooling on the same equipment instead of a second system.
Mini split repair
Service and repair on existing ductless systems, including equipment we didn't install.
Air conditioning replacement
Replacing an older cooling-only system, usually with a heat pump that covers both seasons.
The other manufacturers we install
We're also authorized dealers for Daikin and American Standard, and we service all makes and models whoever installed them. On the hydronic side we work with condensing gas boilers including Viessmann, and with Uponor for in-floor distribution.
Being a Diamond Contractor doesn't make Mitsubishi right for every house. If another manufacturer suits yours better, we'll tell you.
Rebates and incentives
Equipment choice and rebate eligibility are tied together, and it's usually the conditions that trip people up, not the amounts.
In Puget Sound Energy territory, which covers most of the Eastside, PSE only pays its heat pump rebates through contractors holding Recommended Energy Professional or Trade Ally status, and NW Mechanical holds PSE Recommended Energy Professional status. Inside Seattle, City Light runs its own programs on different terms. What you qualify for depends on your utility, the heat you're replacing and sometimes your household income, so we figure out which programs actually apply to your address instead of quoting a headline number.
Our heat pump rebates page lays the regional programs out side by side, including the conditions that disqualify people most often.
Common questions
Does the 12-year warranty apply automatically?
No. The system has to go into a single-family home, be installed by a Diamond Contractor, and be registered with Mitsubishi within 90 days. We handle the registration and pass you the confirmation.
Do I have to take the financing to get the warranty?
The Diamond Advantage program bundles warranty, labor coverage and financing into one purchase, which is the whole idea of it. If you'd rather not finance, say so and we'll quote the work on its own terms. Either way, the financing is subject to credit approval.
What's the labor coverage actually for?
A parts warranty covers the component. It usually won't cover the hours spent diagnosing the fault and fitting the replacement. The JB Warranty coverage in this program picks up that labor for twelve years at no extra cost.
Is Mitsubishi always the right choice?
No. For a house with no ductwork, which is a lot of Seattle, it very often is. For a home with sound ducts already, or a hydronic system worth keeping, the answer might be something else entirely. Being accredited for Mitsubishi doesn't make it right for your house.
Can I combine this with a utility rebate?
Often, yes, though it depends on your utility, your existing heat source and in some programs your household income. The conditions are specific, and they're worth checking before you pick equipment. We'll tell you what your address is actually eligible for.
When do these offers end?
The Fall Rebate closes November 25, 2026, with installation and claims due by December 31. The Diamond Advantage bundle runs to December 31 as well. The Diamond Contractor warranty terms aren't tied to either one and carry on as normal, so if you're weighing a system this fall the timing is worth factoring in.
Talk to us about a Mitsubishi system. Tell us what the house is and what it's doing now, and we'll tell you whether ductless is the right answer, what it would cover, and which programs you qualify for.
Call (206) 900-9231 or request an estimate.
Diamond Contractor program description and the 12-year parts and compressor warranty terms, including the 90-day registration requirement, from Mitsubishi Electric. Diamond Advantage program dates, inclusions and conditions from Mitsubishi Electric homeowner material ME_IN_3399_9-26_H, valid October 1 to December 31, 2026 on qualifying residential M-Series and P-Series installations through participating Diamond Contractors. Financing is subject to credit approval and Synchrony terms. Fall Rebate dates, qualifying equipment and consumer discount amounts from Mitsubishi Electric Fall Rebate program material, valid September 26 to November 25, 2026, with installation and claims due by December 31, 2026. Program terms and rebate amounts change, so confirm current conditions before relying on them. Last reviewed October 2026.
