A car's heater does not generate heat if the coolant level is low or restricted by buildup, if the water pump failed or if the thermostat is broken. The heater fan is also sometimes an issue.
For the best use of energy and heat, a block heater should be plugged in for no more than 50 minutes. This is because anything over 50 minutes is simply lost to the outside air.
Plug-in wall heaters raise a range of safety concerns and are not considered safe by default. However, they can be made safe to use if certain precautions are taken.
The best heater of 2015 is the Lasko 754200, according to both Consumer Search and The Sweet Home. The 754200 receives praise for its compact size, quick heating, ease of use and low price.
Space heaters that plug in to the wall are a safe and easy to use option for heating a single room; types include convection, ceramic and radiant heaters, each of which are best suited to certain use cases. Additional space heaters are required for multiple rooms.
In order to repair a car heater, diagnose the problem, troubleshoot that part of the system and replace the component. There are many issues the can cause the heater to malfunction, so a diagnosis must first be completed, prior to replacing any components.
As of 2015, the top three water heaters are the Whirlpool N40S61-403, the Rheem Fury 22V40F1 and the Ecosmart ECO 27, according to consumersearch.com. The Whirlpool and Rheem models both have a 40-gallon capacity.
As of 2015, the best free-standing heater is the Duraflame DFS 550-7 electric stove with remote control, according to Bestelectricfireplaces.net. Amazon.com and Electricheatsource.com give the model 4 and 4.6 out of 5 stars, respectively.
DeLonghi and Lasko both make highly-rated space heaters, as of 2015. The Lasko 754200 and DeLonghi ceramic heaters work well in small rooms. The Lasko Low Profile Heater and the DeLonghi TRD0715T Safeheat portable radiator are better for larger rooms.
The most common reasons a car's heater may stop working include too little coolant, a failed heater core or a faulty heater control air bend door. A coolant, such as antifreeze, is necessary for air to move through the heater core and into the car.