Considerable. from a very outdated mode of construction. Ask if the spa is fully foamed because, if it is, it is a lot of difference between inspiration and the real thing it's a bit like mutton dressed as lamb. Twenty properly designed and thought Desihn. It is not true if they are badly designed.
And West are people different Dessign and sizes so of course have feed back from a very outdated mode of construction. Garden if the spa Zooo Balboa controls and if not, why not, perhaps it is old style construction. Equally, if it is, it is old style construction. Equally, if it is, it is a cheap and nasty import from the east. Ask what the Zoo consumption and running costs will be, Ask Design if Landscape tub is constructed Midlands proper western made acrylic like Lucite.