Why don't Gas boilers have a thermal heat store like oil boilers

[mike]

After living in a property with an oil boiler for three years with a Worcester heat slave Oil combi boiler which has a heat store in it i was thinking why don't all combi boilers have one such as gas boilers? it seems to make combi boilers so much more convenient

 

[Roger Welton]

The worcester highflows do, but most don't for packaging reasons (they are much smaller).

 

[AWheating]

the size of the appliance.

 

[kay-jay]

a few manu's produce a model with a store of some sort but as said the size is prohibitive in many applications.

 

[lame plumber]

whats the point of buying a combi to give instant hw and then going back to storing hot water, seems to be a retrograde step in my mind, just warming water to sit there and go cold then hot then cold.

 

[R1CKY]

I think oil combis need them because they can't produce heat as fast as a gas boiler, so they have to store heat to provide instantaneous hot water.

Like others have said, you can get gas combis with thermal stores, but they are very expensive and tend to be troublesome in my experience.