Buying Guide
Point-of-Use vs Whole-Home Tankless
Point-of-use tankless (small electric unit at one fixture) vs full whole-home system.
Quick Verdict
Point-of-use tankless: $400-$900 installed. Serves ONE fixture only (e.g., remote bathroom, kitchen sink). Whole-home tankless: $2,854-$4,574 installed. Serves entire house. Use point-of-use ONLY for: distant fixtures, adding to existing tank setup, or supplementing slow hot water delivery to one room. Call (813) 343-2212.
Point-of-Use vs Whole-Home
| Feature | Point-of-Use | Whole-Home Tankless |
|---|---|---|
| Install cost Tampa | $400-$900 | $2,854-$4,574 |
| Serves | 1 fixture | Entire home |
| Power source | Usually electric (110V or 220V) | Gas or electric 200A+ |
| Flow rate | 0.5-1.5 GPM | 6-11 GPM |
| Endless hot water | For that fixture only | For whole house |
| Best use | Distant bathroom, kitchen addition | Whole-home replacement |
| Additional to existing tank | Yes (supplement) | Replaces tank |
What We Recommend
Point-of-use tankless is niche, great for: fixture far from main water heater (long wait for hot water), adding a bathroom, or supplementing existing tank for heavy-use kitchen.
Whole-home tankless is the upgrade path for most tankless customers, replaces the tank, serves everything.
For most Tampa homes, whole-home Rheem tankless is the answer.
FAQ
Electric point-of-use enough?
6 kW unit serves bathroom sink. Shower needs 18 kW+ unit (expensive, requires heavy electrical).
Skip the tank entirely?
Whole-home tankless replaces tank completely. Point-of-use adds TO the system.
Tampa use case?
Most common: remote addition (ADU, guest house, garage conversion) where running hot water line is impractical.
When to Use Point-of-Use Tankless in Tampa
Point-of-use (POU) tankless water heaters are small, electric, single-fixture units that mount near a specific tap to eliminate the cold-water wait. Whole-home tankless units are large, gas-powered systems that replace your entire water heater. They serve very different needs and most Tampa homeowners pick the wrong one at least once.
Point-of-use wins when:
- Remote fixtures with long hot-water runs: A kitchen or bath 40+ feet from the main water heater waits 30-60 seconds for hot water. A POU unit under the sink delivers hot water in 2-3 seconds.
- Garage conversions (ADU, in-law suites): Adding a bathroom or kitchen in a garage conversion where running new hot water supply line from the main heater is expensive.
- Pool bath or outdoor kitchen: Dedicated POU eliminates the need to tap the main water heater.
- Water-saving supplement: Tampa homes with WaterSense fixtures. POU eliminates the 1-2 gallons wasted waiting for hot water at distant taps.
Rheem POU Models for Tampa Homes
- Rheem RTEX-04 (mini-tank): 4 gallon capacity, 120V plug. Not truly tankless but holds hot water at the point of use. $249-$299, $449-$599 installed. Best for hand-wash sinks.
- Rheem RTEX-13 (tankless): 13 kW electric, 240V dedicated circuit. 3.17 GPM at 35-degree rise. $349-$449, $599-$799 installed. Good for single bathroom sink or small kitchen.
- Rheem RTEX-18: 18 kW, 240V. 4.4 GPM. $549-$649, $849-$1,099 installed. Handles a shower or multi-fixture bathroom.
- Rheem RTEX-27: 27 kW, 240V with two 50A breakers. 6.5 GPM. $949-$1,099, $1,499-$1,799 installed. Small whole-home option for 1-bedroom ADU or very small home.
Electrical Requirements Block Most Whole-Home POU Attempts
Here is where most Tampa homeowners hit a wall. A true whole-home electric tankless needs enormous electrical capacity. An 18 kW POU needs a dedicated 75A 240V circuit. An electric whole-home tankless (Rheem RTEX-36 or similar) needs 150A of dedicated capacity, which often exceeds the main service of older Tampa homes.
Typical Tampa electrical service:
- Pre-1980 Tampa home: 100A main service. Cannot support whole-home electric tankless without full panel upgrade ($2,500-$5,000).
- 1980-2010 home: 150A or 200A main. May support whole-home electric tankless if other loads allow.
- 2010+ home: Usually 200A main. Can typically handle whole-home electric tankless.
For Tampa homes, gas whole-home tankless (Rheem RTGH-95DVLN, Navien NPE, Rinnai) is almost always the right whole-home solution. Electric POU makes sense only for specific single-fixture applications.
Cost Comparison: POU vs Whole-Home Gas Tankless
| Solution | Installed Cost | Coverage | Best For |
|---|---|---|---|
| POU 4-gallon mini-tank | $449-$599 | 1 hand-wash sink | Remote powder room |
| POU 13 kW tankless | $599-$799 | 1 sink or small kitchen | Under-sink applications |
| POU 18 kW tankless | $849-$1,099 | 1 shower or bathroom | Garage conversion bath |
| Whole-home gas tankless (Rheem RTGH) | $2,800-$3,800 | Entire home unlimited | Replacing existing tank |
| Whole-home electric tankless (Rheem RTEX-36) | $1,499-$1,799 + panel upgrade often required | Small home only | ADU with 200A service |
Tampa ADU and Garage Conversion Permit Reality
Converting a Tampa garage into a habitable space (ADU) requires:
- Zoning approval for ADU (Hillsborough County: allowed by right in most zones as of 2024)
- Building permit ($250-$450 depending on scope)
- Plumbing permit ($185-$325)
- Electrical permit if new circuits ($100-$185)
- Inspections: rough-in, framing, insulation, final
A POU tankless often simplifies the plumbing permit because you avoid running new 3/4 inch copper supply line from the main heater. Just local water supply to the POU and the POU handles everything else.
When to Combine Both Solutions
Some Tampa homes benefit from both approaches together:
- Whole-home Rheem RTGH gas tankless as the primary system (main bathrooms, kitchen, laundry).
- POU Rheem RTEX-18 added at a remote garage bath or pool bath where hot-water wait is 60+ seconds from the main unit.
Combined install: $3,800-$4,800 total. Eliminates wait time at the remote fixture without requiring a recirculation pump loop.
Frequently Asked Questions
Can I use POU tankless as my whole-home water heater?
Only if your home is small (under 800 sq ft) and has 200A electrical service. Rheem RTEX-36 whole-home electric tankless needs 150A of dedicated capacity, which most older Tampa homes cannot provide without a service upgrade.
What is the difference between mini-tank and tankless POU?
Mini-tanks (Rheem RTEX-04) hold 2.5-4 gallons of pre-heated water for instant use. True tankless (RTEX-13, 18, 27) heats water on demand. Mini-tanks plug into a standard 120V outlet; tankless need 240V dedicated circuit.
Do POU units require a permit in Tampa?
Plumbing permit yes, since you are modifying the water supply. Electrical permit if new dedicated circuit is required. $285-$510 combined typical.
How long do POU tankless units last?
10-15 years for the heating elements. Less than whole-home gas tankless (20-25 years) due to hard-water scale accumulation on the smaller heating element.
Can I install a POU myself?
Florida requires a licensed plumbing contractor for plumbing permit work. For electric circuits, licensed electrician. DIY POU is legal only if you do not pull a permit (which is not recommended for resale or insurance).
What about descaling POU units in Tampa hard water?
Annual descaling recommended, same as whole-home tankless. $149-$199 service. Skip it and the heating element fails in 3-4 years instead of 10.
Will a POU work during a power outage?
No. Electric POU needs 120V or 240V, same as any electric heater.
What if my garage conversion has gas service?
Then a small gas tankless might beat POU electric. Rheem RTG-84 (outdoor gas tankless, $999-$1,199 unit, $1,799-$2,399 installed) handles a full ADU bathroom and kitchen on natural gas with no 240V electrical requirement.
Call (813) 343-2212 for FREE estimates on any POU or whole-home tankless install. Licensed CFC1431159.