A fluid heating apparatus 1 has a fluid circuit 7 arranged to convey a fluid to and from a heat exchanger 3. The fluid circuit is divided into a first branch 41 and a second branch 43 and, in use, the flow rate of the fluid through the first branch is higher than through the second branch. A controller 13, preferably in the form of a thermostatic mixing valve, is arranged to control flow of the fluid through the first and second branches, in response to a control signal. The second branch may include a flow-rate restrictor 11. The apparatus may comprise a fluid store 5, such as an unvented water cylinder, the first fluid circuit conveying water between the heat exchanger and the fluid store. The controller may control the first fluid through the branches in response to a temperature of the fluid so as to maintain a target temperature.
