Choosing between a solar vs gas water heater is one of the choices you notice most on your gas bill and in daily life at home. If you are buying, renting or thinking about replacing your boiler, here is a practical, jargon-free comparison. In Mexico, Google searches for “calentador de agua” (+16%) and “boiler” (+13%) grew over the last 12 months, according to Google Trends: many families are facing this exact decision.
We do not list prices or brands, since they change constantly. What we give you is a way to decide.
How each heater works
Gas water heater (boiler). It heats water with gas, either LP or natural. There are two types: storage models, which keep hot water in a tank, and tankless (instant) models, which heat water only when you open the tap. The Mexican government’s energy-efficiency guide recommends replacing a gas heater that is over 10 years old, preferably with an instant model, which saves more gas.
Solar water heater. It uses the sun’s energy, with no gas or electricity. A collector captures sunlight and heats the water, a tank stores it and pipes carry it to the shower. These systems can be backed up by a gas boiler for cloudy days.
Quick comparison
| Aspect | Gas heater | Solar heater |
|---|---|---|
| Energy source | LP or natural gas | Sun (with gas backup if you want it) |
| Ongoing cost | You buy gas regularly | Reduces gas use |
| Upfront investment | Lower | Higher |
| Maintenance | Drain the tank every 3 months (per manufacturer) | Clean the collector and drain the tank at least once a year |
| Service life | Replacement suggested after 10 years | Estimated 15 to 20 years |
| Space | Little, near the main point of use | Needs a sunny roof |
Maintenance and replacement data come from the Mexican government’s home energy-saving guide. The solar service life is an estimate from a specialized supplier.
How much can a solar heater save?
A press release from El Poder del Consumidor and the Heinrich Böll Foundation (October 2023) says a solar water heater can cut a household’s fossil fuel use by 60% to 80%, and that the investment is recovered in about three years. Keep in mind these are general figures from a civil-society organization [VERIFICAR: payback depends on how much gas you use, the price of gas and the equipment you choose]. To know what you would save, check what you spend on gas each month today.
A useful fact: in Mexico, gas is the main fuel for heating water in 86% of homes, while only 13.4% have a solar heater, according to the same organization.
The hidden cost of a pilot light
If your gas boiler keeps a pilot light on all the time, it uses about 113 kg of LP gas a year, nearly five 20 kg cylinders, according to the government guide. Turning off the pilot when you are away for several days and preferring models with electronic ignition helps you save.
What to check before deciding
- How many people live in the home. The unit size should match your usage; the guide advises choosing the right capacity, because larger units burn more gas.
- Sun on your roof. A solar unit needs a space with good sun during the day [VERIFICAR: orientation, space and roof strength requirements].
- Distance to the shower. The guide suggests installing the heater near the main point of use and in a well-ventilated place, to lose less heat and gas.
- Labels and standards. Look for the yellow energy-efficiency label, the FIDE seal or Energy Star. For gas heaters, standard NOM-003-ENER-2021 took effect in March 2022 and updated the label, which now includes standby gas use, such as a pilot light. For solar heaters, NOM-027-ENER/SCFI-2018 is in force and covers thermal performance, gas savings and safety.
- Your local water. With hard water, scale can affect equipment [VERIFICAR: effect of scale and care by heater type].
- Who installs it. Good installation is key in both cases, especially when gas is involved [VERIFICAR: requirements to install and inspect LP gas at home].
Solar vs gas water heater: which one to choose
- Your own home for many years, sunny roof, high gas use: solar is often a good investment, with a backup boiler.
- Rented home or tight budget today: an efficient gas heater (tankless, with electronic ignition) can be the practical choice, especially if you will not stay long.
- Small household with low use: compare what you spend today. With low use, the savings take longer to show.
- House for sale or purchase: ask what heater it has and how old it is; if the boiler is over 10 years old, consider replacing it.
Tips to use less gas with any heater
- Keep the thermostat on medium or between 32 and 37 °C (about 90 to 99 °F).
- Aim for showers under 7 minutes.
- Bathe children together to use the water that is already hot.
- Check pipes and equipment regularly.
Frequently asked questions
Does a solar heater work on cloudy days?
It heats less, which is why many are installed with a gas backup.
How often does a solar heater need maintenance?
The government guide recommends keeping the collector clean and draining the tank at least once a year.
How long does a gas heater last?
The guide suggests replacing it after 10 years.
Can I have solar and gas together?
Yes. In fact, the guide proposes keeping the gas heater as a backup.
Related reading
Looking for a home and want to review these details?
If you are buying or renting and want to know what to check in the house, message us on WhatsApp at 55 8418 4789 and we will guide you.