Key Takeaways
- Tank water heaters cost $800–$1,500 installed; tankless units cost $2,000–$4,500 installed.
- Tankless units last 20+ years compared to 10–15 years for tank models, potentially offsetting the higher upfront cost.
- Boise’s cold incoming water temperature (around 45°F in winter) means tankless units must work harder—proper sizing is critical.
- Boise’s hard water (8–12 GPG) requires regular descaling maintenance for both types, but especially for tankless units.
When your water heater needs replacing—or you’re building a new Boise home—one of the biggest decisions you’ll face is tankless vs. tank water heater. Both have legitimate advantages, and the right choice depends on your household size, hot water usage patterns, budget, and your Boise home’s specific characteristics. This guide compares both options with Boise-specific factors so you can make an informed decision.
How Each Type Works
Tank Water Heaters (Storage Water Heaters)
A tank water heater stores 30–80 gallons of hot water in an insulated tank, keeping it heated and ready for use at all times. When you open a hot water faucet, preheated water flows from the tank, and cold water enters the bottom to be heated. Most Boise homes use 40- or 50-gallon natural gas tank water heaters.
Tankless Water Heaters (On-Demand Water Heaters)
A tankless water heater doesn’t store hot water. Instead, it heats water instantly as it flows through the unit using a powerful gas burner or electric element. When you open a hot water faucet, cold water travels through the unit, is heated to the set temperature, and delivered on demand. The unit only operates when hot water is flowing.
Side-by-Side Comparison
| Feature | Tank Water Heater | Tankless Water Heater |
|---|---|---|
| Installation Cost | $800–$1,500 | $2,000–$4,500 |
| Lifespan | 10–15 years | 20+ years |
| Energy Efficiency | 60–65% (gas) | 80–98% (gas) |
| Annual Energy Cost (Boise) | $350–$500 | $200–$350 |
| Hot Water Supply | Limited by tank size | Unlimited (continuous) |
| Wait Time for Hot Water | Immediate (stored) | 2–5 seconds delay |
| Physical Size | Large (60″ tall, 24″ wide) | Small (wall-mounted) |
| Maintenance Frequency | Annual flush | Annual descaling + flush |
Boise-Specific Factors to Consider
Cold Incoming Water Temperature
This is one of the most important factors for Boise homeowners considering tankless. In winter, Boise’s incoming water temperature drops to approximately 45°F (compared to 55–65°F in warmer climates). A tankless unit must raise the water temperature by 75°F or more to reach a 120°F output. This greater temperature rise reduces the flow rate a tankless unit can deliver.
A tankless unit rated at 9.5 GPM (gallons per minute) in a warm climate might only deliver 5–6 GPM in a Boise winter. Proper sizing is critical—an undersized tankless unit will struggle to supply multiple simultaneous demands (two showers running at once, for example) during cold months.
Hard Water Impact
Boise’s hard water (8–12 grains per gallon) affects both types of water heaters but in different ways:
- Tank water heaters: Scale accumulates on the bottom of the tank and on heating elements, reducing efficiency by 25–30% over time and shortening lifespan. Annual flushing helps but doesn’t eliminate the problem.
- Tankless water heaters: Scale builds up on the heat exchanger, the most expensive component. Without annual descaling (a vinegar flush), hard water can reduce a tankless unit’s efficiency and eventually cause premature failure.
If you choose either option, consider installing a water softener to protect your investment and extend your water heater’s life.
Natural Gas Availability
Most Boise homes have natural gas service through Intermountain Gas. Gas tankless units are the most popular and cost-effective option. If your home doesn’t have gas (some newer homes in Eagle and Star are all-electric), electric tankless units are available but require a significant electrical panel upgrade (typically 150–200 amps dedicated), adding $500–$1,500 to installation costs.
Energy Savings: Do the Math
Tankless water heaters are 24–34% more energy-efficient than tank models for homes using 41 gallons or less of hot water per day (the average Boise household). Here’s how the savings break down over the life of each unit:
- Annual energy savings: $100–$200 per year with a tankless unit
- Over a 20-year tankless lifespan: $2,000–$4,000 in energy savings
- Over a 12-year tank lifespan: Baseline (no savings)
When you factor in the higher upfront cost of a tankless unit ($1,000–$3,000 more than a tank), the energy savings roughly break even over the life of the unit. The financial advantage of tankless comes from its longer lifespan—you’d need to replace a tank water heater twice in the time a tankless unit lasts once.
Best Brands for Boise Conditions
Tank Water Heaters
- Rheem: Widely available in Boise, excellent warranty support, good performance with hard water
- A.O. Smith: Built-in glass lining resists corrosion, available in high-efficiency models
- Bradford White: Professional-grade quality, sold exclusively through licensed plumbers
Tankless Water Heaters
- Navien: Top choice for Boise—built-in recirculation pump, excellent cold-weather performance, and a buffer tank option that prevents the “cold water sandwich” effect
- Rinnai: Industry leader with a 15-year heat exchanger warranty, performs well with hard water
- Rheem: Good mid-range option with smart home connectivity and solid Boise dealer support
Sizing Guide for Boise Homes
Tank Water Heaters
- 1–2 people: 30–40 gallons
- 3–4 people: 40–50 gallons (most common in Boise)
- 5+ people: 50–80 gallons or consider tankless
Tankless Water Heaters
Size by flow rate, accounting for Boise’s cold winter water temperature:
- Small home (1 shower + 1 faucet simultaneously): 6–7 GPM at 45°F rise
- Medium home (2 showers simultaneously): 8–9 GPM at 45°F rise
- Large home (2+ showers + dishwasher): 10+ GPM or two units in parallel
Maintenance Requirements
Tank Water Heater Maintenance
- Annual flush to remove sediment (especially important with Boise’s hard water)
- Anode rod inspection every 2–3 years (replace when 50%+ depleted)
- Temperature/pressure relief valve test annually
Tankless Water Heater Maintenance
- Annual descaling flush with white vinegar (30–60 minute process)
- Inlet filter cleaning every 6 months
- Venting inspection annually
Learn more about water heater maintenance on our water heater repair page.
Which Should You Choose?
Choose a Tank Water Heater If:
- Your budget is under $1,500 for installation
- You’re replacing an existing tank unit in the same location
- You have moderate hot water needs (1–3 people)
- You prefer simplicity and lower maintenance costs
Choose a Tankless Water Heater If:
- You want unlimited hot water for a larger household
- You’re building new or doing a major renovation (easier to install during construction)
- You plan to stay in your home 10+ years (to recoup the investment)
- You want to free up floor space (garage, utility closet)
- You value long-term energy savings and a 20+ year lifespan
Frequently Asked Questions
How long does it take to install a tankless water heater in Boise?
A typical tankless water heater installation in a Boise home takes 4–8 hours. If you’re replacing an existing tank unit, the plumber needs to upgrade the gas line (tankless units require a ¾” gas line), install new venting (usually PVC direct vent through the wall), and may need to upgrade your electrical connection for the control board. If you’re replacing a tankless with another tankless, installation is faster—typically 2–4 hours.
Can a tankless water heater keep up with Boise’s cold winters?
Yes, but only if properly sized. Boise’s winter incoming water temperature of approximately 45°F means the unit must produce a larger temperature rise than in warmer climates. A unit rated for 9+ GPM should handle most Boise households. For larger homes or high-demand situations, two smaller tankless units installed in parallel provide ample capacity.
Will hard water damage my tankless water heater?
Boise’s hard water (8–12 GPG) will cause scale buildup on the heat exchanger if not maintained. Annual descaling with a vinegar flush is essential. Without it, scale can reduce efficiency, cause error codes, and shorten the unit’s lifespan. Installing a water softener upstream of the tankless unit is the best way to prevent hard water damage and is strongly recommended for Boise homes.
Is a tankless water heater worth the extra cost in Boise?
For many Boise homeowners, yes—especially if you plan to stay in your home long-term. The energy savings of $100–$200/year, combined with a lifespan that’s roughly double a tank unit, typically offsets the higher installation cost. The unlimited hot water supply is also a significant quality-of-life improvement for larger families. However, if you’re on a tight budget or plan to move within a few years, a high-efficiency tank water heater is a perfectly good choice.
Ready to upgrade your water heater? Hyde Park Plumbing installs and services both tank and tankless water heaters throughout the Boise metro area. We’ll help you choose the right system for your home, usage patterns, and budget. Call us at (208) 994-3745 for a free consultation and upfront pricing.