Heaters: a guide to choosing the best one in Portugal (types, consumption and safety)

Heaters: a guide to choosing the best one in Portugal (types, consumption and safety)

When you are looking for heaters (or “portable heating”), you will find several types: fan heaters , convectors , oil radiators , thermal emitters , infrared heaters , and in some cases, gas heaters . The right choice depends mainly on 3 things: room size , usage time , and the level of comfort you desire.

Important note: if the goal is to heat the house cost-effectively, DECO indicates that solutions such as air conditioning (heat pump) and pellet stoves tend to have a better cost/benefit ratio and environmental impact than portable heaters used as the "main solution".
Still, portable heaters make a lot of sense for "spot" heating (e.g., office, bedroom before bed, bathroom in the morning).

1) First, choose the "use": heat up quickly or maintain comfort for hours?

Rapid warm-up (cold spells):

  • Typically, it's a fan heater , or some models use infrared (they heat up "instantly").

Prolonged comfort (several hours):

  • Convector , oil radiator or thermal emitter (more stable, less "blowing")

2) Types of heaters: advantages and when to choose each one

A) Fan heater (heater with a "fan")

For: quickly warming a small area (e.g., cold feet in the office, a bathroom for a short time).
Key points to know:

  • DECO reports that there are "conventional" and "ceramic" fan heaters; in tests, conventional heaters proved more effective at transferring heat than ceramic heaters, which may take longer to heat up and end up being more expensive with prolonged use.

  • Safety: DECO has already warned about models that have failed electrical safety tests — here it's worth buying reliable brands/lines and using them carefully.

B) Electric convector

For: heating a room in a simple and relatively even way, without a strong "blast".
Tip: Look for thermostat settings and adjustment modes so you don't always have to leave it at maximum.

C) Oil radiator

For: longer use, "gentle" and constant heat.
Why: It heats up more slowly, but can maintain comfort even after being switched off (thermal inertia).

D) Thermal emitter / radiant panels (wall)

For: prolonged use and consistent heat, often with programming.
Warning: "being a transmitter" doesn't work miracles — it still depends on isolation, power, and operating time. (Good for those who want to schedule and maintain a routine.)

E) Infrared / halogen / quartz

For: directly warming "the person" / area (good local sensation), often in small rooms and for short-term use.
Note: DECO mentions limitations in some types (e.g., temperature control/heating time), so it's important to choose one with a thermostat and adequate safety features.

F) Gas heaters (and other fuels)

It only makes sense with equipment designed for indoor use , good ventilation , and proper maintenance. There is a risk of carbon monoxide (CO) from combustion in enclosed spaces.

3) Power (W) and division size: a practical rule

As a reference for purchasing portable heaters, there are guides that indicate approximately:

  • ~ 1000 W for up to 15 m² (indicative)
    and tables for similar areas (ranges per m²) to help avoid buying "too little" or "too much".

✅ UmBox Tip: If the house has poor insulation (old windows, cold walls), choose a higher level or focus on local heating (heating the room/area where you are) and not the whole house.

4) Consumption and cost: how to calculate in 10 seconds

Formula:
Cost (€) = (W ÷ 1000) × hours × price per kWh

This is the typical recommended method for estimating monthly consumption (power × hours / 1000) and then multiplying by the price per kWh.

Quick example: 2000 W (2 kW) heater, 3 hours/day
2 x 3 = 6 kWh/day → multiply by your tariff (€/kWh) and by 30 days.

5) Energy label: why it doesn't always appear on electric heaters

There is an energy labelling regulation for “local space heaters” (Regulation (EU) 2015/1186), but the European Commission explains that this act excludes electric local heaters from the scope of the label.
➡️ In practice: in many electric heaters, compare mainly power (W) , thermostat , timer , modes and safety .

6) Safety: the checklist that prevents problems (very important)

Recommendations aligned with DGS guidelines:

  • Do not use a gas stove, oven, or charcoal to heat your home .

  • Turn off heaters before going to bed or leaving the house to reduce the risk of fire/poisoning.

  • Keep away from curtains/fabrics and always use on a stable surface.

Carbon monoxide (CO): pay close attention to combustion.

INEM warns of an increase in CO poisonings and recommends:

  • Do not use combustion equipment in completely enclosed spaces.

  • ensure adequate ventilation

  • If symptoms occur (headache, nausea, fainting): get some fresh air, go outside and contact 112 / CIAV 800 250 250 .

Tips for heating more efficiently while spending less.

  • Heat the room you're in (with the door closed) instead of "trying to heat the whole house".

  • Use a thermostat and timer (avoid setting it to maximum all the time).

  • Improve the basics: seals on windows, thick curtains, carpets (fewer leaks).

  • If you have air conditioning (heat pump), use it as a "base" and the portable heater only as a supplement — DECO highlights AC as a cost-effective solution.

FAQ

Which heater is the most economical?
It depends on usage (time on, room type, insulation). For heating the house as the primary solution, DECO highlights air conditioning (heat pump) as a cost-effective option.

Is a ceramic fan heater better?
DECO reports that, in tests, conventional fan heaters were more effective at transferring heat than ceramic ones.

Can I use a gas stove to heat the house?
The DGS (Directorate-General of Health) recommends against using gas stoves/ovens/coal stoves for domestic heating.