Same-Day Service
Most service calls handled same-day across Spokane and Coeur d'Alene.
Tankless Water Heaters
Hot water on demand — no tank, no waiting, no end.
Tankless water heaters heat water as you use it instead of storing 40+ gallons all day long. The result: endless hot water (no more cold showers after back-to-back use), 30–40% lower operating cost than a tank, and roughly twice the lifespan — 15–20 years vs 8–12 for a tank.
The trade-off is up-front cost and install complexity: gas-line sizing, dedicated venting, and properly sized electrical for indoor units. We handle all of it. Most installs are completed in 1–2 days with same-evening hot water.
- Endless hot water Properly sized tankless never runs out — even with multiple fixtures running.
- 30–40% more efficient No standby heat loss — you only pay to heat water you actually use.
- Long lifespan 15–20 year lifespan with maintenance — roughly twice as long as a tank.
- Wall-mounted Frees up the floor space your old tank occupied — basements, closets, garages.
When It Makes Sense
Is tankless right for your home?
Tankless is a great fit for most households but not every situation. Quick checks:
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Large household
4+ people with overlapping hot water needs — tankless eliminates the cold-shower problem.
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Multiple bathrooms
Simultaneous shower + dishwasher + laundry use is where tankless shines.
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Want to lower bills
Operating cost is 30–40% lower than a comparable tank for most households.
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Need floor space back
Tankless wall-mounts — frees up a 2x2 footprint where the tank used to live.
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Tank near end of life
Best time to consider tankless — install cost spreads against the new-tank cost you'd be paying anyway.
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New construction or remodel
Rough-in for tankless is similar cost to tank — and worth it for the long-term efficiency.
What We Install
Every tankless type and brand
Indoor and outdoor, gas and electric, single-unit and multi-unit configurations.
- Indoor gas tankless Whole-home gas units from Navien, Rinnai, A.O. Smith, and Noritz.
- Outdoor tankless Outdoor-rated units that skip indoor venting requirements.
- Electric tankless Point-of-use and whole-home electric tankless for gas-free properties.
- Multi-unit systems Two-unit cascade configurations for very high simultaneous demand.
- Recirculation pumps Built-in or external recirc for instant hot water at distant fixtures.
- Gas line upsizing Tankless typically needs a larger gas line than a tank — included in our quote.
- Direct-vent installation Concentric or twin-pipe venting — code-compliant install for indoor units.
- Annual descaling Required service to maintain warranty and prevent heat-exchanger failure.
How It Works
A tankless install, start to finish
Most installs done in 1–2 days with same-evening hot water.
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Free home assessment
We check gas supply, venting options, and household demand to size and locate the unit.
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Fixed-price quote
Equipment, gas line, venting, electrical — all in writing, no surprises.
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Install
Old unit removed, new unit mounted, gas + water + vent + electrical connected and tested.
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Walk-through
Tech walks you through controls, warranty registration, and Avista rebate paperwork.
Current Specials
Save on the work your home needs most.
Why Choose Mainstream
Upfront Pricing
Flat-rate pricing approved before work begins — no surprises on the invoice.
Licensed & Insured
Fully licensed in Washington and Idaho, bonded, and insured for your protection.
Satisfaction Guaranteed
If it isn't right, we make it right. Period.
Curious about tankless? Free in-home estimate.
Same-day service across Spokane & Coeur d'Alene — flat-rate pricing, no surprises.
What Our Customers Say
Don't just take our word for it — hear from our satisfied customers
★★★★★
Ricky Saldana the technician that came out was fantastic. He was so knowledgeable about my plumbing issues and his recommendations were spot on. He was on time and very pleasant to work with. I would highly recommend him for any plumbing work that needs to be done.
Thanks Ricky for all of your input.
★★★★★
Jake was on time and very good about looking at my furnace. I appreciate all his help. I reccomend him and mainstream electric very highly. thank you Sharon Scott
Maintenance Membership
Join the Care Club
Total home service care, on a schedule.
Members get priority scheduling, seasonal HVAC tune-ups, an annual plumbing & electrical safety inspection, and exclusive discounts — for less than the cost of a single emergency call.
- Priority scheduling
- Seasonal HVAC tune-ups
- Annual safety inspection
- Exclusive member discounts
- Free dispatch on repairs
- No long-term contracts
Tankless Water Heaters — Frequently Asked Questions
Is tankless right for my house?
Most homes — yes. The exceptions are very small households with low hot-water demand (where the up-front cost is hard to justify) and homes where gas-line upsizing isn’t feasible. We assess at the in-home estimate and tell you honestly whether tankless is worth the investment in your specific case.
Does tankless really save money?
Operating cost is 30–40% lower than a tank for most households — the savings come from eliminating standby heat loss. Up-front cost is higher; payback is usually 5–10 years on operating costs, plus the longer lifespan (15–20 years vs 8–12) doubles the total value picture.
How long does install take?
Most tank-to-tankless conversions take 1–2 days. Straight tankless replacements (when you already have one) are typically same-day. Larger projects requiring electrical service upgrades or major gas-line work can take a third day.
What rebates are available?
Avista offers rebates of up to $300 for qualifying gas tankless installations. Federal Inflation Reduction Act tax credits apply to qualifying heat-pump water heaters (but not standard tankless). We handle all the paperwork.
Do tankless units need maintenance?
Yes — annual descaling. Hard-water minerals build up on the heat exchanger, reducing efficiency and shortening lifespan. The descaling service is separate from tank-flush and required to maintain most manufacturer warranties.
What's warrantied?
Manufacturer warranties run 12–15 years on the heat exchanger and 3–5 years on parts (registration required, which we handle for you) plus our 2-year Mainstream labor warranty.
*Offers cannot be combined with other promotions or applied to dispatch fees. No cash value. Must present offer at time of service. Call for details.
