Last Christmas, my partner and I stumbled across our dream flat. Reasonable rent, a decent commute and solid amenities, it was perfect for us.

As a consumer journalist, I try to practice what I preach, so within hours of signing our tenancy agreement, I researched the best deals to save money on our energy bills.

What I hadn't realised was that, despite my efforts, we'd end up not stuck on an expensive variable tariff with high standing charges like plenty of households, but shelling out on two sets of standing charges. 

And there's no way to avoid it.

When we moved into our home in January, I discovered that while our usual electricity supply would be provided by an ordinary supplier (which has since gone bust), our heating and hot water would come from a 'heat network'.

I confess, I'd only heard of these in passing before we moved. A heat network provides heating and hot water to buildings - primarily blocks of flats - from a central source. 

It means that the individual flats in a building don't need their own boiler or heat pump.

In theory, they're more flexible and also have thermal storage, meaning they can stash away power and move demand away from the National Grid at peak times. 

But what it means for myself and my partner is that while we pay a direct debit to our energy company for electricity from the mains, we have to manually top up online with the provider of the heat network to have any heating and hot water.

Once our balance drops to zero, our hot water switches off. It takes hours to update, which means that there have been countless times when I've been caught out and had to take a cold shower.

It has been a pain, but nothing out of the ordinary if you're used to prepayment meters. The price was also manageable, topping up about £40 a month, on top of the approximately £50 of electricity from our new electricity supplier, Octopus Energy.

It wasn't until I looked at fixing our bill with Octopus that I decided to compare the prices between the two and, crucially, how much we were paying in standing charges.

Standing charges have been a particular bugbear of mine. We do not use a lot of electricity because we're mostly out during the day, and like other low usage households, the majority of our bills are made up of standing charges.

The heat network was charging 11.09p.kWh for electricity and a whopping 116.77p per day for standing charges.

While the unit price was significantly cheaper than April's 27.03p/kWh on the price cap, the standing charge was nearly double that (53.8p per day).

It meant that of the £40 we were topping up every month, £34.80 was spent on standing charges.

I got irate and prepared to send some angry emails, but realised there was nothing we could do. There isn't a competitive market because the provider is the only way our block has access to heating and hot water. We'd have to grin and bear it.

An engineer from the network broke our boiler in July. Three months later and it still hasn't been fixed, although we do still have access to our hot water.

After some back and forth with the network, and still no heating, I looked deeper into why we were topping up more regularly if we had no heating and had normal hot water usage.

A letter soon arrived explaining that our unit prices were dropping from 11.09p/kWH to 7.16p/KWh. Great news, but it didn't explain our higher bills.

Not so brilliantly, our standing charges were increasing from 116.77p/day to 123.67p/day.

It means that we now pay roughly £37.20 in heat network standing charges plus £12.84 for Octopus' standing charges (42.8p per day) every month. That's over half of our total energy bill.

There is no protection from this racket. We can't fix our bill or dispute it, and we're not eligible for any support.

Heat networks don't currently fall under Ofgem's remit, although they are expected to finally be regulated from next year. This is welcome news for the approximately half a million who currently have little protection from these rip-off charges and have no way to switch suppliers.

It doesn't fix the problem that we have two sets of standing charges, though. Even if standing charges on heat networks fall to price cap levels, we'll still be paying double. 

We can absorb the costs, but there will be plenty of households that can't.

The heat network says a further review of the charges will be made in six months time. 

I hope by then Ofgem will have cracked down on heat networks charging their customers extortionate prices simply for supplying heating and hot water. 

Are you part of a heat network and being overcharged? Get in touch angharad.carrick@thisismoney.co.uk