“暖气”的英语是heating(英国英语)或heat(美国英语)。
现在大部分暖气系统的原理是：在一个地方把水加热，然后热气顺着已经安好的管道到达各个住户。这种系统叫central heating，也就是我们经常说的“集中供暖”。
有时候，我们会说这样的话，“我家的暖气坏了，摸着根本就不热。”这个“暖气”是指与供暖系统连接的散热器，对应的英语是radiator。
用暖气就要涉及到暖气费，“暖气费”的英语是heating costs(请注意是复数)，而“交暖气费”叫pay the heating bill，现扩充一下交各种费的说法：
pay the phone bill 交电话费
pay the electricicty bill/electric bill 交电费(electric bill是非正式说法)
pay the gas bill 交燃气费
pay the water bill 交水费
以下例句供大家参考：
【例】Switch the heating on I'm cold!
(来源：Oxford Advanced Learner's English-Chinese Dictionary)
【例】Central heating is a heating system for buildings. Air or water is heated in one place and travels round a building through pipes and radiators.
(来源：Collins COBUILD Advanced Learner's Dictionary 5th Edition)
【例】The first of October is "central heating day", when many people switch on their radiators for the winter. Central heating is just another mod-con of contemporary living, but it's done much more than warm us up.
(来源：BBC官网，地址为http://news.bbc.co.uk/2/hi/uk_news/magazine/8283796.stm)
【例】The indoor temperature can also be modified using a monitoring system similar tocentral heating.
(来源：CNN官网，地址为http://edition.cnn.com/2015/04/08/tech/water-house-matyas-gutai/index.html)
【例】Senators also wanted to offer rebates to higher-income households, seniors living on Social Security and disabled veterans and $1 billion in heating assistance to help lower-income people pay their heating bills.
(来源：CNN官网，地址为http://money.cnn.com/2008/02/07/news/economy/stimulus_senatevote_thurs/index.htm)
