Installing a quiet graphics card into your computer and mining on it is probably okay (assuming it's your personal desktop, and not owned by your employer). Worst case, you might be asked to stop leaving your system on all the time.
Trying to conceal a dedicated mining rig in the office, however, probably isn't the greatest idea.
Think about what you'd pay keeping it at home: (Ignoring costs to comfort, additional/reduced AC/heating costs, and other things that are difficult to estimate.)
Consider the most powerful rig you could reasonably expect to hide or have ignored by most coworkers. It's debatable (would the company notice an unauthorized system on the network, or someone constantly on the guest wifi, would they notice a spike in power costs, etc.), but I'm thinking 8x 1080ti cards on 2 PSUs mounted on a solid frame. Maybe somewhere around 1'x1'x2'. Back to estimating power costs:
Assuming each card draws about 250W when pegged, that brings us to 2000W. If we estimate a total of 100W for all other components, that brings the total power estimate up to 2100W.
Over the course of 30 days, that brings us to 1,512 kWh. Suppose that, on average, you pay $0.20 per kWh. For many miners, this would be considered rather expensive, so I'm being generous with the electricity costs you'd expect to save. (It's in tiers, but it doesn't really make sense to say whether the mining rig was responsible for the "first" or "last" part of the total electricity use.)
This brings us to about $300 per month. Is saving $300 per month worth the possibility of receiving a reprimand? I don't think so, but I suppose it would depend on how secure you feel about your job. (I mean, if you're a tenured professor conducting "research"...
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Anyhow, back on topic. Attempting to conceal a mining rig at your workplace is probably not worth it. Ask the
appropriate people for permission. (In that case, be prepared to accept a blunt "no" or "not for free".)
Keep in mind that commercial facilities generally aren't billed by the simple kWh that you're used to seeing at home. In my experience, commercial power bills tend to look quite a bit more complicated, although I've never been the employee responsible for processing them. Off the top of my head, I can't say whether or not a mining rig would have a greater impact on costs for a commercial power bill or a residential power bill. Those are details you'd have to work out at your workplace.
A sample explanation of a large commercial power bill:
https://www.csu.org/CSUDocuments/understandinglargebills.pdf