Answering the question “which gas hot water heater should I buy?” this guide highlights top on‑demand gas models suited for homes, apartments, and small commercial spaces. The selections favor energy efficiency, temperature stability, and compact installation. Ideal buyers include: homeowners upgrading from tanks, condo dwellers needing space‑saving options, and vacation homes seeking reliable hot water without preheating delays. Below is a quick summary table of five strong options to compare at a glance.
- Tankless Water Heater Natural Gas — 4.3 GPM, 100,000 BTU
- MIZUDO 120,000 BTU Natural Gas Tankless — 5.1 GPM
- APUS Natural Gas Tankless Water Heater — 4.42 GPM
- APUS Propane Tankless Water Heater — 4.42 GPM
- CAMPLUX 5L Portable Tankless Water Heater — 1.32 GPM (Propane)
| Product | BTU / GPM | Fuel | Best For |
|---|---|---|---|
| Tankless Water Heater Natural Gas, Indoor | 100,000 BTU / 4.3 GPM | Natural Gas | Medium homes with multiple fixtures |
| MIZUDO 120,000 BTU Natural Gas Tankless | 120,000 BTU / 5.1 GPM | Natural Gas | Whole‑home use with several outlets |
| APUS Natural Gas Tankless Water Heater | 95,000 BTU / 4.42 GPM | Natural Gas | 2–3 fixtures with stable temps |
| APUS Propane Tankless Water Heater | 95,000 BTU / 4.42 GPM | Propane | Off‑grid or no natural gas access |
| CAMPLUX 5L Portable Tankless Water Heater | 1.32 GPM | Propane | Camping, RVs, short trips |
Tankless Water Heater Natural Gas, Indoor
Key features include a 100,000 BTU burner with a 4.3 GPM flow, enabling continuous hot water for 2–3 points like kitchens and bathrooms. It uses a V3.0 self‑modulating temperature system to keep water within ±1°F, supporting a comfortable shower even with cold outside temperatures. Four‑season mode automatically adjusts output, and a kitchen mode sets a precise 100°F for dishwashing. Best for: mid‑sized homes needing reliable, energy‑efficient, on‑demand hot water. Limitation: complex installation may require professional plumbing.
MIZUDO 120,000 BTU Natural Gas Tankless
Designed for whole‑house use, this unit supports up to 5.1 GPM, ideal for homes with multiple simultaneous fixtures. It features smart temperature control to maintain steady output within ±1°F and uses advanced gas modulation and copper heat exchangers for efficiency. Best for: households with several outlets needing consistent temperature control. Caution: installation guidance is important to ensure correct venting and vent pipe sizing.
APUS Propane Tankless Water Heater
This unit delivers 95,000 BTU with 4.42 GPM, offering two showers plus a sink with stable temperatures. It uses a smart CPU to keep water temperature within ±1°F and claims up to 98% thermal efficiency with segmented combustion. Best for: off‑grid or propane‑only homes seeking space‑saving hot water. Limitation: propane supply and venting requirements must be met for safe operation.
APUS Natural Gas Tankless Water Heater
With 95,000 BTU and 4.42 GPM, this model supports 2–3 fixtures with precise temperature control between 95°F and 140°F. It emphasizes high efficiency and space savings, aided by a 0.66 GPM low‑flow start. Best for: homes needing reliable supply for multiple fixtures while conserving energy. Caution: ensure adequate ventilation and venting compatibility for safe operation.
Buying Guide
What to consider when choosing a gas tankless water heater:
- Flow rate and BTU needs: Match the unit’s GPM and BTU to your household’s hot water demand and number of fixtures.
- Temperature stability: Look for ±1°F control for steady showers even during peak usage.
- Fuel type and installation: Choose natural gas for typical homes or propane for off‑grid setups; verify venting requirements and clearance space.
- Smart features: WiFi/App control and precise setpoints can help with maintenance and energy monitoring.
- Efficiency metrics: A higher efficiency and better UEF provide long‑term energy savings; consider heat exchanger material and combustion technology.
- Installation considerations: Some units are indoor only, others offer indoor/outdoor flexibility; confirm local codes and venting needs.
- Support for future needs: If you anticipate expanded fixtures, select a higher GPM model or one with multi‑point support.
FAQ
- What size gas tankless heater do I need for a 2–3 fixture home?
Choose models around 4.0–5.0 GPM with 95,000–120,000 BTU for comfortable multi‑point use. - Do gas tankless heaters require venting?
Yes. Most indoor units need venting to safely expel combustion byproducts; confirm vent type and diameter. - Is temperature stability important?
Yes. A ±1°F range helps prevent unexpected hot or cold shocks during showers and dishwashing. - Can I install a gas tankless heater myself?
Installation involves plumbing, gas supply, and venting; professional installation is often recommended. - Are propane units suitable for homes with natural gas?
Propane units are designed for propane systems; ensure fuel availability and venting compatibility for safe operation. - What maintenance is required?
Periodic descaling, vent inspection, and gas line checks help maintain efficiency and safety.